JP7792218B2 - packaging box - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies. Delivered by Dynapac Co., Ltd. to the Nikko Factory of Mitsubishi Corporation Life Sciences Co., Ltd. from July 1 to September 21, 2021.

This disclosure relates to a packaging box made of corrugated cardboard sheet suitable for use in packaging products and the like.

Conventionally, packaging boxes have been known that include a main body formed by folding a cardboard sheet into a cylindrical shape, and lid flaps that extend from the edges of the main body and close the top and bottom openings. Also known are wraparound packaging boxes in which a cardboard sheet is folded around the periphery of a product, and flaps extending from the edges of the cardboard sheet that surround the product cover its sides (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2002-370728

In conventional packaging boxes equipped with lid flaps that close the top and bottom openings, a pair of inner flaps and a pair of outer flaps extend from the edge of the main body near the opening. When packaging a product or other item, the product or other contents are placed inside the main body through the opening, and then the inner flaps are folded back at their borders with the main body to close part of the opening (hereinafter, the state in which the flaps close the opening will also be referred to as the "closed state"). Next, the outer flaps are folded back at their borders with the main body so that they overlap the folded inner flaps, closing the box. Adhesive tape is then applied across the leading edges of the outer flaps to secure them in the closed state.

Conventional packaging boxes like those described above have the problem that the outer flaps secured with adhesive tape can lift up due to the repulsive force of the cardboard sheet. There is also the problem that when the opening is closed with the outer flaps, the leading edge of the flaps can overlap and be secured with adhesive tape. In these cases, the central portion of the surface closed by the outer flaps is raised, which not only makes the box look bad but also reduces the stability of the packaging box. For example, there is the problem of poor stability when multiple packaging boxes are stacked together.

The objective of this disclosure is to provide a packaging box that reduces the repulsive force of the cardboard sheet and allows the opening to be properly closed and secured with a flap.

To achieve the above object, the present disclosure provides the following means.
The packaging box of the present disclosure is a packaging box made of cardboard sheet, and is provided with a main body portion having a plurality of side portions connected in a cylindrical shape and having an opening surrounded by the side portions, and a flap extending from an opening edge that is the edge of the side portion on the side of the opening and closing at least a part of the opening, the flap having at least a front side edge that extends approximately parallel to the opening edge on the front side in the direction in which the flap extends, an inner side surface that faces inward and to which the side portions of the main body portion face when the opening is closed, and an outer side surface on the opposite side to the inner side surface, and the front part of the outer side surface has a width that is larger than the front side edge. The inner surface has a recessed line portion recessed inward, extending approximately parallel to the tip side edge at a predetermined distance from the opening edge, a first inclined portion extending inward from the opening edge toward the recessed line portion in an area closer to the opening edge than the recessed line portion, and a first tip portion between the recessed line portion and the tip side edge, and the tip portion of the inner surface has a second inclined portion extending outward at an inclination toward the tip side, and a second tip portion between the second inclined portion and the tip side edge, and the second tip portion is located on the tip side of the recessed line portion.

According to the packaging box disclosed herein, the flap that closes the opening of the main body has a first inclined surface and a second inclined surface at the leading edge of the outer and inner surfaces, respectively. The leading edge of the outer surface also has a recessed line that is recessed inward, and a first leading edge. The leading edge of the inner surface also has a second leading edge further forward of the recessed line. In other words, the leading edge of the flap of the packaging box disclosed herein has its outer and inner surfaces each formed into a predetermined shape, and is configured so that its thickness decreases toward the leading edge. This reduces the repulsive force of the cardboard sheet at the leading edge of the flap. Furthermore, when the flaps are secured with adhesive tape, the outer corners of the flap tips are prevented from protruding outward. Even if the flaps are closed with their leading edges overlapping, it is expected that the leading edges of each flap will deform, causing the overlapping flaps to naturally shift, eliminating the overlap at the leading edges.

In the above disclosure, it is preferable that the first tip portion extends toward the tip side at a different angle than the first inclined portion, and the second tip portion extends toward the tip side at a different angle than the second inclined portion.

By doing this, the repulsive force of the cardboard sheet at the leading edge of the flap is reduced. Furthermore, even if the flap is closed with its leading edge overlapping, the force applied to the flap is distributed between the first and second leading edges, and it is expected that the overlapping flaps will naturally shift and the leading edge overlap will be resolved.

In the above disclosure, it is preferable that the first inclined portion extends inwardly from the opening edge side, at a greater angle than the second inclined portion.

By doing this, the leading edge of the outer surface of the flap is inclined over a wider range than the leading edge of the inner surface, further reducing the repulsive force of the cardboard sheet on the flap when the opening is closed.

The packaging box disclosed herein has the advantage of being able to reduce the repulsive force of the cardboard sheet and provide a packaging box that can secure the opening properly closed with a flap.

FIG. 1 is a perspective view illustrating a packaging box according to an embodiment of the present invention. FIG. 1 is a perspective view illustrating a packaging box according to an embodiment of the present invention. FIG. 2 is a diagram showing the front surface (outer surface) of the developed view of the packaging box according to the present embodiment. FIG. 2 is a diagram showing the rear surface (inner surface) of the developed view of the packaging box according to the present embodiment. FIG. 10 is a diagram showing an example of a cross section of a flap. FIG. 10 is a diagram showing another example of a cross section of a flap. FIG. 1 is a diagram illustrating a test. Fig. 8(a) is a diagram showing a state where conventional packaging boxes fixed with adhesive tape are stacked, and Fig. 8(b) is a diagram showing a state where packaging boxes according to this embodiment fixed with adhesive tape are stacked. 9A is a diagram showing a state where packaging boxes according to this embodiment, which are secured with adhesive tape, are stacked up, and FIG. 9B is a diagram showing a state where conventional packaging boxes, which are secured with adhesive tape, are stacked up. Fig. 10(a) is a diagram illustrating a state in which a conventional packaging box is fixed with adhesive tape, and Fig. 10(b) is a diagram illustrating a state in which the packaging box according to this embodiment is fixed with adhesive tape.

A packaging box 10 according to one embodiment of the present disclosure will be described primarily with reference to Figures 1 to 10. In the following description, front-to-back, left-to-right, and top-to-bottom directions will refer to the directions shown in the figures unless otherwise specified. The side of the packaging box 10 on which the product is stored will be referred to as the inside, and the opposite side as the outside. Furthermore, when the packaging box 10 is formed, the surface of the sheet material 1 that will face inward will be referred to as the inside surface or back surface, and the surface that will face outward will be referred to as the outside surface or front surface.

Arrows and diagonal lines indicating directions in each figure are included to facilitate understanding of the relationships between the figures and the shapes of each component or part. Therefore, the content of this disclosure is not limited to the directions indicated in each figure. Diagonal lines do not necessarily indicate cross-sectional views.

1. Description of the Structure The packaging box 10 of this embodiment is a packaging box formed by folding a sheet material 1 formed into the shape shown in Figures 3 and 4 at predetermined locations. In this embodiment, the sheet material 1 is a cardboard sheet.

The packaging box 10 includes a cylindrical main body 2 composed of rectangular side sections 3, 5, 7, and 9, flaps 23, 25, 27, and 29 that close an opening A on the upper side of the main body 2, and flaps 53, 55, 57, and 59 that close an opening B on the lower side of the main body 2. Opening B is not shown. Hereinafter, flaps 23, 25, 27, and 29 and flaps 53, 55, 57, and 59 will be collectively referred to as "flaps."

Side portion 3 and side portion 7 are approximately the same size. Side portion 5 and side portion 9 are also approximately the same size. In the unfolded state, side portion 3 is connected to side portion 5, and the side of side portion 5 opposite side portion 3 is connected to side portion 7. The side of side portion 7 opposite side portion 5 is connected to side portion 9 (see Figures 3 and 4). A handle portion 30, defined by a roughly U-shaped cut line, is provided in the center of side portion 5 and side portion 9. Handle portion 30 is pushed inward during use to serve as a handle for packaging box 10.

A glue tab 21 is connected to the side of side portion 3 opposite side portion 5. An adhesive portion 22 is provided at the end of side portion 9 opposite side portion 7. The glue tab 21 is fixed to the adhesive portion 22 using a known fixing method when folding the sheet material 1 to assemble the packaging box 10. The main body 2 is formed by fixing the glue tab 21 to the adhesive portion 22. The glue tab 21 and adhesive portion 22 are crushed so that they are thinner than the other portions, preventing them from becoming thicker than the other portions when the glue tab 21 and adhesive portion 22 are fixed.

A vertical crease 20 is provided between each of the side surfaces 3, 5, 7, and 9 to facilitate folding. A vertical crease 20 is also provided between the side surface 3 and the glue tab 21.

The flap 23 extends from the opening edge 33a on the opening A side of the side surface 3 in a direction intersecting the direction in which the side surfaces 3, 5, 7, and 9 are arranged (see Figure 4). Hereinafter, in Figures 3 and 4, the direction in which the side surfaces 3, 5, 7, and 9 are arranged will be referred to as the longitudinal direction of the sheet material 1, or simply as the longitudinal direction.

Flap 25 extends from opening edge 35a on the same side as opening edge 33a of side portion 5, similar to flap 23. Furthermore, flap 27 extends from opening edge 37a on the same side as opening edge 33a of side portion 7, similar to flap 23. Furthermore, flap 29 extends from opening edge 39a of side portion 9, similar to flap 23. Hereinafter, the side of the flap opposite side portions 3, 5, 7, and 9 will also be referred to as the "tip side." Furthermore, the side of the flap facing side portions 3, 5, 7, and 9 will also be referred to as the "base side." Approximately in the center of flap 27, there is an opening portion 40 defined by a convex cut line. The opening portion 40 is pushed inward or cut away during opening, and is the part that the user places their hand on to open the package.

Flaps 25, 29 are inner flaps that are folded inward along opening edges 35a, 39a to close at least a portion of opening A. As shown in Figures 3 and 4, leading edge 45 of flap 25 is bent in a crank shape, and flap 25 has a generally L-shaped configuration in which the vertical width on flap 27 side is narrower than that on flap 23 side (see Figures 3 and 4).

The leading edge 49 of the flap 29 is bent in a crank shape, and the flap 29 has a generally L-shaped configuration, with the flap 27 side being narrower in the vertical direction than the side that will be adjacent to the flap 23 when the main body 2 is assembled (see Figures 3 and 4). In other words, the flaps 25 and 29 are formed so that the portion corresponding to the opening portion 40 is cut out when the opening A is closed.

Flaps 23 and 27 are outer flaps that are positioned outside flaps 25 and 29 when folded inward along opening edges 33a and 37a to close opening A (see Figure 2). The leading edge 43 of flap 23 extends substantially parallel to opening edge 33a. Furthermore, the leading edge 47 of flap 27 extends substantially parallel to opening edge 37a.

When closed, flaps 23 and 27 are sized so that their leading edges do not overlap, and so that they cover substantially the entire opening A. Specifically, the lengths of flaps 23 and 27 in a direction intersecting the longitudinal direction of sheet material 1 are set so that, when closed, leading edges 43 and 47 abut or a gap is left between leading edges 43 and 47. In other words, flaps 23 and 27 are arranged so that the sum of their respective lengths in the vertical direction in Figures 3 and 4 is substantially the same as or slightly shorter than the length of side portion 5 and side portion 9 in the longitudinal direction of sheet material 1.

Flap 53 extends in the opposite direction from flap 23 from opening edge 33b on the opening B side of side portion 3. Similarly, flap 55 extends from opening edge 35b of side portion 5, flap 57 from opening edge 37b of side portion 7, and flap 59 from opening edge 39b of side portion 9, similar to flap 53. Hereinafter, opening edges 33a, 35a, 37a, 39a and opening edges 33b, 35b, 37b, 39b will be collectively referred to as "opening edges 33, 35, 37, 39."

Flaps 55 and 59 are inner flaps that are folded inward along opening edges 35b and 39b to close at least a portion of opening B. The leading edge 65 of flap 55 extends generally parallel to opening edge 35b. Furthermore, the leading edge 69 of flap 59 extends generally parallel to opening edge 39b.

When closing the opening B, the flaps 53 and 57 are folded inward along the opening edges 33b and 37b, and are positioned outside the flaps 53 and 57. The leading edge 63 of the flap 53 extends approximately parallel to the opening edge 33b. Furthermore, the leading edge 67 of the flap 57 extends approximately parallel to the opening edge 37b.

When flaps 53 and 57 are closed, their leading edges do not overlap, and flaps 53 and 57 are sized to cover substantially the entire opening B. Specifically, the lengths of flaps 53 and 57 in a direction intersecting the longitudinal direction of sheet material 1 are set so that, when flaps 53 and 57 are closed, leading edges 63 and 67 abut or leave a gap between them. In other words, flaps 53 and 57 are arranged so that the sum of their respective lengths in the vertical direction in Figures 3 and 4 is approximately the same as or slightly shorter than the length of side portion 5 and side portion 9 in the longitudinal direction of sheet material 1.

Rings 15 are provided on the inner surface of the sheet material 1 at positions corresponding to the opening edges 33, 35, 37, and 39 (see Figure 4). The creases 15 are linear depressions formed using a known method, and are continuous linear depressions that extend a predetermined depth toward the outer surface (see Figures 5 and 6). In other words, the creases 15 are linear depressions of a predetermined width that extend outward using a known method.

A set of creases 11, 13 extending in the longitudinal direction of the sheet material 1 is provided near the opening edges 33, 35, 37, and 39 on the outer surface of the sheet material 1 (see Figure 3). The creases 11, 13 are linear depressions formed using a known method, and are continuous linear depressions that extend to a predetermined depth toward the back surface, i.e., the inner surface (see Figures 5 and 6). In other words, the creases 11, 13 are linear depressions that extend inward to a predetermined depth and a predetermined width using a known method.

Ring 11 is provided closer to side portions 3, 5, 7, and 9 than opening edges 33, 35, 37, and 39, and extends parallel to opening edges 33, 35, 37, and 39. Ring 13 is provided on the opposite side of opening edges 33, 35, 37, and 39 from scoring 11, and extends parallel to opening edges 33, 35, 37, and 39.

Depressions 17 are provided on the inner surface of the sheet material 1 at positions a predetermined distance forward from the opening edges 33, 35, 37, and 39. The depressions 17 are strip-shaped depressions with a predetermined width that are parallel to the opening edges 33, 35, 37, and 39. The depressions 17 are provided forward of the positions corresponding to the ruled lines 13 on the outer surface (see Figures 5 and 6).

2. Description of the Tip Side of the Flaps Next, the shape of the tip sides of the flaps 23, 27, 29 and the flaps 53, 55, 57, 59 will be described using the flap 23 as an example, mainly with reference to Figures 5 and 6. Note that for the purpose of explanation, Figures 5 and 6 illustrate the angle of inclination of the outer and inner surfaces, the depth and dimensions of the recesses, and other characteristics in a manner that makes them clearer, but the angle of inclination, the depth and dimensions of the recesses, and other characteristics are not limited to these.

The leading portion of the outer surface of the flap 23 is formed so as to slope inward as it approaches the leading edge, from a first start position 70 that is a predetermined distance away from the leading edge 43 toward the opening edge 33a. Furthermore, a recessed line 73 extending parallel to the leading edge 43 is provided near the leading edge 43 of the flap 23 and a predetermined distance away from the opening edge 33a (see Figures 3, 5, and 6).

The recessed line portion 73 is a linear recess that recesses inward. In other words, the recessed line portion 73 is a portion that has been crushed linearly inward by a predetermined depth and a predetermined width. In this embodiment, the recessed line portion 73 is located approximately 5 mm away from the tip side edge 43 toward the opening edge 33a, as will be described below. However, the recessed line portion 73 may be located in a different position as long as it is near the tip side edge 43. The sloped outer surface area from the first start position 70 to the recessed line portion 73 is the first sloped portion 71.

On the outer surface, a first tip portion 75 is provided between the recess line portion 73 of the flap 23 and the leading edge 43. The first tip portion 75 extends toward the leading side at an angle different from that of the first inclined portion 71. In other words, the first tip portion 75 is a portion that is further forward than the recess line portion 73 and is crushed in a different direction than the recess line portion 73.

The tip portion of the inner surface of the flap 23 is formed so that it slopes outward as it moves toward the tip from a second start position 80, which is a predetermined distance away from the tip edge 43 toward the opening edge 33a.

A strip-shaped second tip portion 79 of a predetermined width is provided at the tip end of the inner surface of the flap 23, extending parallel to the tip edge 43. The second tip portion 79 is provided adjacent to the tip edge 43 in a portion further forward than the recess line portion 73. The second tip portion 79 extends toward the tip at a different angle than the second inclined portion 77, which will be described in detail below. The second tip portion 79 is a portion that is crushed in a different direction than the recess line portion 73.

The area between the second start position 80 and the second tip portion 79 is the second inclined portion 77. The second start position 80 is located further forward than the first start position 70 (see Figures 5 and 6). In other words, the first inclined portion 71 is inclined inward from the opening edge 33a toward the tip side more than the second inclined portion 77.

In this embodiment, the second tip 79 has a width of approximately 3 mm, but the width may be different. While Figure 5 illustrates the second tip 79 extending at an inward angle, the angle at which the second tip 79 extends is not limited to this. For example, the second tip 79 may extend in approximately the same direction as the portion of the flap 23 on the opening edge 33 side (see Figure 6), or may be inclined at another angle.

In this embodiment, the leading ends of flaps 27, 29, 53, 55, 57, and 59 are similarly provided with a first inclined portion 71, a recessed line portion 73, a first tip portion 75, a second inclined portion 77, and a second tip portion 79. Note that flaps 55 and 59 may not be provided with the first inclined portion 71, the recessed line portion 73, the first tip portion 75, the second inclined portion 77, and the second tip portion 79. Alternatively, flap 25 may also be similarly provided with the first inclined portion 71, the recessed line portion 73, the first tip portion 75, the second inclined portion 77, and the second tip portion 79. In other words, all flaps may be provided with the first inclined portion 71, etc.

3. Evaluation Test of Packaging Box Below, the results of a comparison test with a conventional packaging box conducted to evaluate the performance of the packaging box 10 according to this embodiment are shown. In the following tests, each test was conducted using the samples shown in the table below (see Table 1).

Sample (1) is a conventional packaging box with the same shape as packaging box 10, but with only ruled lines 11 and 13 and a recessed portion 17. In other words, it is a conventional packaging box that does not have any structure corresponding to first inclined portion 71, recessed line portion 73, first tip portion 75, second inclined portion 77, or second tip portion 79 on the tip side of the flap. Sample (2) is a packaging box identical to packaging box 10.

Sample (3) is a packaging box with the same characteristics as packaging box 10. However, in sample (3), the length of flaps 23, 25 differs from that of sample (2). Specifically, flaps 23, 25 of sample (3) are long enough that leading edge 43 and leading edge 47 abut when closed. Sample (4) is a packaging box of the same shape as sample (3), but is a conventional packaging box whose flaps do not have the lines 11, 13, the recessed portion 17, or the features corresponding to first inclined portion 71, recessed line portion 73, first leading portion 75, second inclined portion 77, and second leading portion 79.

3-1 Sealing Performance Test Using Sample (3) and Sample (4), a test was conducted to compare the heights of the flaps secured with adhesive tape while the top and bottom openings of each were closed (see Figure 7). The measurement results are shown in the table below (see Table 2). The test was conducted on empty boxes with no contents inside, with 50 samples of each type. Each sample, with its opening closed with a flap and secured with adhesive tape, was placed near the wall, and the height of each packaging box was measured and the average value calculated. Note that the reference value in the table below is the calculated value for the height of the packaging box in the closed state, taking into account the thickness of the cardboard sheet.

The height of the packaging box in the closed state will be close to the standard value if the resilience of the cardboard sheet is suppressed. On the other hand, if the resilience of the cardboard sheet is not suppressed, the measured value will be large. In other words, the results of this test can confirm the extent to which the resilience of the cardboard sheet is suppressed.

As shown above, sample (3), which is the packaging box 10 according to this embodiment, showed a smaller difference from the reference value compared to sample (4), which is a conventional packaging box. This indicates that the packaging box 10 according to this embodiment suppresses the repulsive force of the cardboard sheet, and maintains fixation with adhesive tape with minimal bulging.

3-2 Test for overlapping during sealing In this test, samples (3) and (4) were used to check the percentage of packaging boxes that were closed with the tips of the outer flaps overlapping when the top and bottom openings were closed with flaps using a sealing machine and secured with adhesive tape. The measurement results are shown in the table below (see Table 3). The test was conducted on empty boxes with no contents inside, with 50 samples for each, and the number of packaging boxes that were secured with the tips of the outer flaps overlapping was counted.

For sample (4), a conventional packaging box, approximately half (26 boxes) were closed with the tips of the outer flaps overlapping and secured with adhesive tape. This means that the rate of packaging boxes secured in this state was approximately 52%. On the other hand, for sample (3), a packaging box 10 of this embodiment, only four boxes were secured in this state, for a rate of approximately 8%. This shows that the packaging box 10 of this embodiment is able to prevent the tips of the outer flaps from being secured in an overlapping state when sealing.

This is thought to be because in the packaging box 10, at least the outer flaps (flaps 23, 27, 53, 57) are provided with first tip portions 75 and second tip portions 79, further weakening the repulsive force at the tips of the flaps, preventing such overlapping. In other words, even if the tips of the flaps overlap, the first tip portion 75 or second tip portion 79 at the tips of the flaps may deform, or the force may be dispersed at the first tip portion 75 or second tip portion 79, causing the tips of the flaps to shift and eliminating the overlap.

3-3 Stability Confirmation Test When Stacked A 1 L water bag was placed in each of samples (1) to (4), and the flaps were closed and fixed with adhesive tape. A number of samples were stacked and the appearance was checked.

The test results are shown in Figures 8(a) to 9(b).
In sample (4), which is a conventional packaging box, it was confirmed that each packaging box was tilted and stacked in an unstable state (see FIG. 9(b)). On the other hand, in samples (2) and (3), which are packaging boxes 10 of this embodiment, it was confirmed that each packaging box was stacked in a stable state with less tilt (see FIGS. 8(b) and 9(a)). That is, in the packaging box 10 of this embodiment, the repulsive force of the cardboard sheet is reduced and the tips of the outer flaps are prevented from closing in an overlapping state, so the surface closed by the flaps is maintained in a flatter state. This shows that multiple packaging boxes 10 can be stacked in a stable state.

It was also confirmed that sample (1) was stacked in a more stable manner than sample (4), a conventional packaging box. Because sample (1) has lines 11, 13 and recesses 17, these configurations also reduce the repulsive force of the cardboard sheet on the flaps to a certain extent, and it is thought that the surface closed by the flaps remains relatively flat.

3-4 Comparison of Appearance When Sealed Samples (3) and (4) were closed and secured with adhesive tape, and a test was conducted to compare their appearances. In sample (4), a conventional packaging box, it was confirmed that the outer flaps 23a and 27a were tilted upward toward the boundary where the leading ends of the two flaps faced each other due to the repulsive force of the cardboard sheet. Furthermore, it was confirmed that the corner C at the leading end of flap 27a was protruding outward due to the repulsive force (see Figure 10(a)).

On the other hand, in sample (3), which is the packaging box 10 of this embodiment, it was confirmed that the repulsive force of flaps 23, 27 was suppressed, and the inclination toward the boundary between the two flaps was suppressed. In other words, compared to sample (4), it was confirmed that flaps 23 and 27 were fixed in a flatter state. It was also confirmed that corner portion C at the tip of the flap did not protrude, and that its surface was fixed with adhesive tape in a smooth state (see Figure 10 (b)).

4. Effects According to the packaging box 10 configured as described above, the outer surface of the leading end of the flap is formed so as to slope inward toward the leading end, and is provided with the first inclined portion 71, the recessed line portion 73, and the first leading end 75. Similarly, the inner surface of the leading end of the flap is formed so as to slope outward toward the leading end, and is provided with the second inclined portion 77 and the second leading end 79.

In other words, the outer and inner surfaces of the tip portion of the flap are inclined so that the thickness gradually becomes thinner toward the tip than toward the opening edge 33, and the flap is formed in a flattened shape to form the specified shape.

By doing this, the repulsive force at the tip of each flap is weakened, allowing the closed flaps to be closed and secured in a flatter state compared to conventional packaging boxes. Furthermore, the first tip 75 and second tip 79 are provided further forward than the recessed line 73, weakening the repulsive force at the tip end of the flaps. Therefore, for example, when the closed flaps are secured with adhesive tape, the corners at the tips of flaps 23, 27, 53, and 57 are more likely to deform. In other words, when the closed flaps are secured with adhesive tape, the corners of the outer flaps are prevented from protruding outward.

As a result, compared to conventional packaging boxes, the packaging box can be closed and secured in a flatter state. Furthermore, multiple packaging boxes can be stacked in a more stable state. Furthermore, because the repulsive force at the tip of the flap is weakened, it is expected that, for example, when placing contents into the packaging box 10, the contents will not come into contact with the tip of the open flap and be damaged.

Furthermore, because the resilience of the flaps at their leading edges is weakened, even if the leading edges of the flaps overlap when closing the packaging box 10, the leading edges of the flaps deform, and the overlap is likely to naturally resolve. For example, let us consider a state in which the inner leading surface of the flap 23 overlaps the outer leading surface of the flap 27 when the flaps 23 and 27 are closed, i.e., the second leading edge 79 of the flap 23 overlaps the first leading edge 75 of the flap 27. In this case, the first leading edge 75 and the second leading edge 79 are located further forward than the recessed line 73, further weakening the resilience of the cardboard sheet. Therefore, the force of closing the flaps deforms the leading edges of the overlapping flaps, causing the flaps 23 and 27 to shift, and the overlap at their leading edges is likely to resolve. In other words, the second leading edge 79 of the flap 23 and the first leading edge 75 of the flap 27 can be prevented from becoming fixed in an overlapping state.

As a result, when the packaging box 10 is sealed using, for example, a sealing machine, the leading edges of the flaps are less likely to become stuck in an overlapping position compared to conventional packaging boxes. Furthermore, compared to conventional packaging boxes, the packaging box can be closed and secured in a flatter position, allowing the packaging boxes to be stacked in a more stable state.

Furthermore, the first tip 75 is formed to extend at a different angle from the first inclined portion 71, and the second tip 79 is formed to extend at a different angle from the second inclined portion 77. By doing this, even if the tips of the flaps overlap when closing the packaging box 10, for example, the force is distributed between the first tip 75 and the second tip 79, making it easier for the overlap to naturally disappear.

For example, we will explain the state in which, when flaps 23 and 27 are closed, the inner surface of the leading edge of flap 23 overlaps the outer surface of the leading edge of flap 27, i.e., the second leading edge 79 of flap 23 overlaps the first leading edge 75 of flap 27. In this case, because the first leading edge 75 and the second leading edge 79 are formed as described above, the force applied to the leading edges of the overlapping flaps to close the flaps is easily dispersed. Furthermore, this force can cause the overlapping portions of the leading edges of the flaps to deform, easily causing flaps 23 and 27 to shift and the overlap to be resolved. In other words, it is possible to prevent the second leading edge 79 of flap 23 and the first leading edge 75 of flap 27 from becoming fixed in an overlapping state.

As a result, when the packaging box 10 is sealed using a sealing machine, for example, the tips of the flaps are less likely to become stuck in an overlapping position compared to conventional packaging boxes. Furthermore, the packaging box can be closed and secured in a flatter position compared to conventional packaging boxes. It also becomes possible to stack packaging boxes in a more stable position.

Furthermore, the first inclined portion 71 extends at an angle from a portion closer to the base than the second inclined portion 77. In other words, the first start position 70 is located closer to the base than the second start position 80, and the leading portion of the outer surface of the flap is inclined over a wider range than the inner surface. This reduces the resilience of the flap, allowing the packaging box to be fixed in a flatter state when closed compared to conventional packaging boxes. This also makes it possible to stack packaging boxes in a more stable state.

The packaging box 10 also has a set of creases 11 and 13 on its outer surface. Furthermore, creases 15 are provided on the inner surface at positions corresponding to the opening edges 33, 35, 37, and 39, and depressions 17 are provided on each flap at positions beyond the creases 13 on the outer surface. These configurations also reduce the resilience of the flaps in the packaging box 10.

Furthermore, the lines 11, 13, and 15 and the recessed portions 17 of the packaging box 10 make it easier to fold the flaps outward. In other words, the lines 11, 13, and 15 and the recessed portions 17 of the packaging box 10 reduce the force required to fold the flaps in the direction opposite to the closing direction (hereinafter also referred to as "outward folding force").

Specifically, because crease 13 is located close to depression 17, when the flap is folded outward, the flap bends at crease 13. The presence of depression 17 reduces the outward folding force when folding the flap outward at crease 13. Furthermore, because the outward folding force at crease 13 is smaller than the outward folding force at crease 11, the crease when folding the flap outward is at crease 13. In other words, when the flap is folded outward, the crease does not straddle crease 11 and crease 13. Furthermore, because depression 17 is located on the inside surface of the flap, it does not affect the stacking pressure strength of packaging box 10.

The technical scope of the present disclosure is not limited to the above embodiment, and various modifications can be made without departing from the spirit thereof. For example, the first inclined portion 71, the recessed line portion 73, the first tip portion 75, the second inclined portion 77, and the second tip portion 79 may be provided only on the flap that closes the upper opening. That is, the first inclined portion 71, the recessed line portion 73, the first tip portion 75, the second inclined portion 77, and the second tip portion 79 may be provided only on the flaps 23, 25, 27, and 29. Alternatively, the first inclined portion 71, the recessed line portion 73, the first tip portion 75, the second inclined portion 77, and the second tip portion 79 may be provided only on the outer flaps. That is, the first inclined portion 71, the recessed line portion 73, the first tip portion 75, the second inclined portion 77, and the second tip portion 79 may be provided only on the flaps 23, 25, 53, and 57. In this way, the packaging box 10 can be manufactured using a simple process. Alternatively, the first inclined portion 71, the recessed line portion 73, the first tip portion 75, the second inclined portion 77, and the second tip portion 79 may be provided on all flaps. Furthermore, the lines 11 and 13 and the recessed portion 17 may be provided only on the flaps 23, 25, 27, and 29.

DESCRIPTION OF SYMBOLS 1...Sheet material 2...Main body portion 3, 5, 7, 9...Side portion 10, 10a...Packaging box 11, 13, 15...Rule 17...Depression portion 20...Vertical ruled line 21...Glue margin portion 22...Attachment portion 23, 23a, 25, 27, 27a, 29...Flaps 33a, 33b, 35a, 35b, 37a, 37b, 39a, 39b...Opening edge 53, 55, 57, 59...Flaps 43, 45, 47, 49, 63, 65, 67, 69...Front side edge 71...First inclined portion 73...Depression line portion 75...First front portion 77...Second inclined portion 79...Second front portion A, B...Opening

Claims (2)

a main body having a plurality of side surfaces connected in a cylindrical shape and an opening surrounded by the side surfaces;
a plurality of flaps extending from respective opening edges of the side surface portion that are sides of the opening and that close at least a portion of the opening;
A packaging box made of a cardboard sheet,
The plurality of flaps comprise a set of inner flaps extending from each of a pair of side surfaces arranged at positions opposite each other and folded at the opening edge to close at least a part of the opening, and a set of outer flaps extending from each of the opening edges of another pair of side surfaces different from the side surface surfaces from which the inner flaps extend and folded at the opening edge to overlap the inner flaps folded at the opening edge to close at least a part of the opening,
Each of the outer flaps has a front side edge extending substantially parallel to the opening side on the front side in the direction in which the outer flap extends;
the opening is closed, the opening is closed, and the side surface of the main body portion faces the inside, and the side surface of the main body portion faces the outside opposite to the inside surface,
The tip portion of the outer surface is provided with a recessed line portion recessed inward, extending substantially parallel to the tip side edge at a predetermined distance closer to the opening side edge than the tip side edge, a first inclined portion in a region closer to the opening side than the recessed line portion and extending inwardly as it slopes from the opening side edge toward the recessed line portion, and a first tip portion between the recessed line portion and the tip side edge,
The tip portion of the inner surface is provided with a second inclined portion that extends outwardly as it approaches the tip side, and a second tip portion between the second inclined portion and the tip side edge,
the second tip portion is provided on the tip side of the recess line portion ,
the first inclined portion extends inwardly from the opening edge side relative to the second inclined portion,
When the outer flaps are folded inward at the opening edge, the leading edge of one of the outer flaps abuts against the other outer flap.
packaging box. the first tip portion extends toward the tip side at an angle different from that of the first inclined portion,
The second tip portion extends toward the tip side at an angle different from that of the second inclined portion.
The packaging box according to claim 1.