Packaging box

Abstract

To provide a packaging box with a simple structure, which reliably prevents contamination and also has a high tamper-proof effect.SOLUTION: A packaging box of the present invention has: a plurality of side walls 14, 16, 18, 20; a lid piece 32 continuing to the side wall 14 and closing one opening end of the cylinder; and a pair of flaps 62, 86 continuing to a pair of side walls 16, 20 located on either side of the side wall 14 and overlapping the reverse face of the lid piece 32. The lid piece 32 is provided with a bendable weakening wire 44 and a locking piece 48. The pair of flaps 62, 86 has a locking section 68 into which a locking piece 48 is inserted to lock. When closing the open end of the cylinder with the lid piece 32, the lid piece 32 is bent at the weakening line 44, the locking piece 48 protrudes in the vicinity of the weakening line 44, and the locking piece 48 is inserted into the locking section 68 of the flaps 62, 86. In the sealed state, the lid piece 32 is superposed on the pair of flaps 62, 86 to block one opening end of the cylinder, and the locking piece 48 is locked to the locking section 68 of the flaps 62, 86.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a packaging box in which a lid surface and side flaps are overlapped with no gaps when sealed to close the box. [Background technology]

[0002] Conventionally, there is a packaging box in which a box-forming piece punched out integrally from a sheet such as paper is folded and glued, four side walls forming the box are assembled into a square tube, and an opening at the end of the square tube is closed with a lid piece that is continuous with one side wall. Such a packaging box is composed of four side walls connected in parallel, a lid piece provided at the end of the side wall, and a flap formed at the end of the other side wall, and an insert piece is provided at the tip of the lid piece via a fold line. When closing the opening at the end of the square tube, each flap is folded from the side wall, the lid piece is folded over on top of the flap, and the insert piece is folded from the lid piece along the fold line and inserted into the back side from the end of the facing side wall to lock it.

[0003] However, when the lid is closed, the lid is slightly elastically deformed and curved outward, creating a gap between the lid and the flap, which can easily cause foreign objects to get mixed in and can easily tip over when the lid is placed on the bottom for display. In order to solve this problem, some have been devised to eliminate the gap between the lid and the flap. For example, in the case of a tip-prevention packaging box disclosed in Patent Document 1, a pair of side edges of the lid are cut out in a substantially W-shape toward the center of the lid, and the W-shaped central portion forms a locking portion that protrudes outward. The pair of flaps are provided with slits into which the locking portion of the lid is inserted. When the lid is folded over the flap to close, the locking portion of the lid is inserted into the slit of the flap to lock the lid and the flap together. This can eliminate the gap between the lid and the flap, reduce the elastic deformation of the curved lid, and make it into a shape close to a flat surface, preventing tipping over.

[0004] In addition, the pharmaceutical packaging box disclosed in Patent Document 2 has a foldable modified flap. When the modified flap is covered with a lid to close the opening, it is forcibly folded under the lid into the opening surface and comes into close contact with the inner surface of the lid by its own restoring force. This eliminates the gap between the lid and the flap, preventing the intrusion of foreign matter and improving safety, and also preventing deformation and improving the product image. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-112722 A [Patent Document 2] Japanese Patent Application Publication No. 11-227756 Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of the tip-prevention packaging box of Patent Document 1, a pair of side edges of the lid piece are cut out in a substantially W-shape toward the center of the lid piece, which reduces the area of ​​the lid piece and reduces the overlap with the flap, resulting in an insufficient effect in preventing the intrusion of foreign matter. Also, in the case of the pharmaceutical packaging box of Patent Document 2, the flap and the lid piece are not engaged with each other, resulting in an insufficient effect in preventing tampering.

[0007] The present invention has been made in consideration of the problems in the background art described above, and has an object to provide a packaging box that has a simple structure, reliably prevents the intrusion of foreign matter, and has a high degree of tamper-proofing. [Means for solving the problem]

[0008] The present invention is a packaging box which consists of a single box-forming piece, and which has a plurality of side walls assembled to a cylindrical body, a lid piece which is continuous with one of the side walls and closes one open end of the cylindrical body, and a pair of flaps which are continuous with a pair of side walls located on both sides of the side wall on which the lid piece is provided and are overlapped on the back surface of the lid piece, the lid piece is provided with a weakened line by which the lid piece can be folded, and a locking piece located in the vicinity of the weakened line, and the pair of flaps are each provided with a locking portion into which the locking piece is inserted and locked, and when the lid piece is folded at the weakened line, the locking piece protrudes in the vicinity of the weakened line, and the protruding locking piece is inserted into the locking portion of the flap, and in a sealed state, the lid piece is overlapped on the pair of flaps to close one open end of the cylindrical body and the locking piece is locked to the locking portion of the flap, and the lid piece and the flaps are overlapped and closed without any gaps.

[0009] A fold-over piece is provided on the side edge of the cover piece so as to be folded over onto the back surface of the cover piece, and the fold-over piece has a weakened line formed thereon and continues to the cover piece, and the locking piece is provided near the weakened line of the fold-over piece. The folded piece may be glued to the underside of the lid piece.

[0010] A curved or bent cut line is provided along the weakened line, both ends of the cut line are continuous with the weakened line, the middle part of the cut line is located closer to the side wall on which the lid piece is provided than the weakened line, and the inner part of the cut line does not have the weakened line, and the inner side of the cut line becomes the engaging piece, which protrudes from the lid piece when the lid piece is folded at the weakened line.

[0011] The pair of flaps have fold lines, and the locking portion is provided between the fold lines and the ends of the flaps, and the locking piece is locked to the locking portion when the flap is folded in half at the fold lines.

[0012] The weakened line passes near the center of the lid piece and extends in a direction extending generally parallel to the boundary between the lid piece and the side wall, and the locking pieces are provided on both sides of the center of the lid piece.

[0013] The weakened line is provided reaching both side edges of the lid piece, and the side edge of the lid piece along the weakened line is provided with a V-shaped notch recessed toward the center of the lid piece, and the locking piece is formed on the side edge of the V-shaped notch close to the side wall.

[0014] The locking portion is a through hole or a cut line that passes through the thickness of the flap. Effect of the Invention

[0015] The packaging box of the present invention has a simple structure, reliably prevents the intrusion of foreign objects, and has a high degree of tamper-proofing. The top cover and the flap can be stacked and closed without any gaps between them, and it is possible to prevent the intrusion of foreign objects through the gaps on both sides of the top cover. [Brief description of the drawings]

[0016] [Figure 1] 1A and 1B are perspective views showing an assembled state of a packaging box according to a first embodiment of the present invention, and FIG. 1C is a perspective view showing a sealed state. [Diagram 2] 1 is a development view of a packaging box according to a first embodiment of the present invention as viewed from the front side of the paper. FIG. [Diagram 3] 1 is a development view of a packaging box according to a first embodiment of the present invention as viewed from the back side of the paper surface. FIG. [Figure 4] FIG. 2 is a partially enlarged development view of the packaging box according to the first embodiment of the present invention as viewed from the front side of the paper. [Diagram 5] 13A and 13B are perspective views showing an assembled state of a packaging box according to a second embodiment of the present invention, and FIG. 13C is a perspective view showing a sealed state. [Figure 6] FIG. 11 is a development view of a packaging box according to a second embodiment of the present invention as viewed from the front side of the paper. [Figure 7]13A and 13B are perspective views showing an assembled state of a packaging box according to a third embodiment of the present invention, and FIG. 13C is a perspective view showing a sealed state. [Figure 8] FIG. 11 is a development view of a packaging box according to a third embodiment of the present invention, as viewed from the front side of the paper. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figs. 1 to 4 show a first embodiment of the present invention, and a packaging box 10 of this embodiment is provided by assembling box-forming pieces 12 formed by punching a paper sheet. Fig. 2 is a development view of the box-forming piece 12 seen from the front, and the box-forming piece 12 has four rectangular side walls forming a box, a back surface 14, a side surface 16, a front surface 18, and a side surface 20, which are provided in this order in parallel to each other. The back surface 14, the side surface 16, the front surface 18, and the side surface 20 have the same length in the width direction in which they are connected, and the lengths in the connecting direction are such that the back surface 14 and the front surface 18 are long and almost equal to each other, and the side surfaces 16 and 20 are slightly shorter and almost equal to each other. An adhesive piece 22 is provided on the side edge of the back surface 14 to be glued to the back surface of the side surface 20 when the packaging box 10 is assembled. The adhesive piece 22, the back surface 14, the side surface 16, the front surface 18, and the side surface 20 are separated by fold lines 24, 26, 28, and 30, respectively.

[0018] At one end of the back surface 14 in a direction perpendicular to the connecting direction of the adhesive piece 22 and the side surface 16, a rectangular top cover piece 32 is provided, separated by a fold line 34. At the end of the top cover piece 32 opposite the fold line 34, an insertion piece 36 is provided, separated by a fold line 38. At a pair of side edges of the top cover piece 32 positioned approximately perpendicular to the fold line 34, a pair of fold-back pieces 40 are provided, each separated by a fold line 42.

[0019] The pair of fold-back pieces 40 are symmetrical with each other, are rectangular and long in the direction along the fold line 42, and are long enough to reach the fold lines 38 and 34, and the side edge 40a opposite the fold line 42 is parallel to the fold line 42, and the distance between the fold line 42 and the side edge 40a is shorter than half the distance between the pair of fold lines 42 of the top cover piece 32, and here is about one-fifth of that of the top cover piece 32. The end 40b of the fold-back piece 40, which is continuous with the fold line 34, is formed by a straight line located at about 45° to the extension of the fold line 34, and one end of the end 40b coincides with the intersection of the fold line 42 and the fold line 34, and the opposite end reaches the side edge 40a. End 40c opposite end 40b is a straight line parallel to fold line 38 and contacts fold line 42 at a position slightly shifted toward fold line 34 from the end of fold line 38.

[0020] A weakened line 44 is provided that passes near the center of the top cover piece 32 and is generally parallel to the fold lines 34 and 38. The weakened line 44 is formed, for example, by a pressed line, and serves as a hinge for folding the top cover piece 32. The weakened line 44 continues to a pair of fold-back pieces 40 on both sides and reaches the side edge portion 40a. As shown in Fig. 4, the fold-back piece 40 has a curved cut line 46 that protrudes toward the end portion 40b at a position along the weakened line 44.

[0021] Both ends of the cutting line 46 are continuous with the weakened line 44, and the middle part of the cutting line 46 is located closer to the end 40b than the weakened line 44, i.e., closer to the extension line of the fold line 34. The inside part of the cutting line 46 does not have the weakened line 44, and when the folded piece 40 is folded using the weakened line 44 as a hinge, the inside of the cutting line 46 becomes a locking piece 48 that protrudes flush with the part of the folded piece 40 on the end 40c side. A plurality of auxiliary cutting lines 50 extending toward the end 40b side are provided on the side edge of the cutting line 46 on the end 40b side, and the auxiliary cutting lines 50 assist the locking piece 48 to be pulled out from the part of the folded piece 40 on the end 40b side by the cutting line 46.

[0022] A first bottom lid piece 52 is provided at the end of the back surface 14 opposite to the fold line 34, separated by a fold line 54. The first bottom lid piece 52 is formed in a trapezoid shape with the fold line 54 as the lower base, and the upper base parallel to the fold line 54 is the end 52a. The length from the fold line 54 to the end 52a is the length located near the center line of the bottom part in the assembled state of the packaging box 10, that is, about half the width of the side faces 16, 20. The part of the end 52a on the side of the side face 16 is provided with a substantially triangular bottom glued piece 56 separated by a fold line 58. The fold line 58 is provided in a direction intersecting with the fold line 54. A small square first bottom lid piece insertion piece 60 protruding outward from the end 52a is integrally provided at the position opposite to the bottom glued piece 56 on the end 52a. The shape of the side edge 60a of the first bottom flap insertion piece 60, which is continuous with the end 52a, bulges outward in a semicircular shape, and a fold line 61 is provided at the base end of the bulging part, and the fold line 61 is a straight line that intersects with the end 52a at an obtuse angle. The intersection of the fold line 61 and the end 52a is located near the center of the bottom of the packaging box 10.

[0023] A trapezoidal upper flap 62 is provided at the end of the side surface 16 that is connected to the fold line 34 of the back surface 14, separated by a fold line 64. The fold line 64 is the lower base of the upper flap 62, and the upper base that is parallel to the fold line 64 is the end 62a. The length from the fold line 64 to the end 62a is approximately equal to the length from the fold line 42 of the folded piece 40 to the side edge 40a. The end 62b of the upper flap 62 that is continuous with the fold line 26 is formed as a straight line located at approximately 45° to the fold line 64, coincides with the end 40b of the folded piece 40, and the boundary line with the end 40b is separated by a separation cut line 66. A through hole 68 is formed in the center of the upper flap 62, which is an engagement portion into which the engagement piece 48 of the folded piece 40 is inserted in the assembled state. The through hole 68 is formed through the thickness of the upper flap 62, has a semicircular shape, and is surrounded by a straight portion parallel to the fold line 26 and a curved portion that bulges toward the extension of the fold line 28. The length of the through hole 68 in the direction parallel to the fold line 26 is slightly longer than the length of the locking piece 48 in the direction perpendicular to the fold line 26.

[0024] At the end of the lateral surface 16 opposite the fold line 64 is a generally triangular bottom flap 70 bounded by a fold line 72 .

[0025] The end 18a of the front surface 18 adjacent to the fold line 64 of the side surface 16 is left empty. At the end of the front surface 18 opposite to the end 18a, a second bottom lid piece 74 of the same shape as the first bottom lid piece 52 is provided, separated by a fold line 76. The second bottom lid piece 74 is formed in a trapezoid shape with the fold line 76 as the lower base, and the upper base parallel to the fold line 76 is the end 74a. The length from the fold line 76 to the end 74a is the length located near the center line of the bottom part when the packaging box 10 is assembled, that is, about half the width of the side surfaces 16, 20. At the portion of the end 74a on the side surface 20 side, a bottom glued piece 78 of a substantially triangular shape is provided, separated by a fold line 80. The fold line 80 is provided in a direction intersecting the fold line 76. A small rectangular second bottom lid piece insertion piece 82 protruding outward from the end 74a is integrally provided on the opposite side of the end 74a from the bottom glue piece 78. The side edge 82a of the second bottom lid piece insertion piece 82, which is continuous with the end 74a, is shaped to bulge outward in a semicircular shape, and a fold line 84 is provided at the base end of the bulged portion, and the fold line 84 is a straight line that intersects with the end 74a at an obtuse angle. The intersection of the fold line 80 and the end 74a is located near the center of the bottom of the packaging box 10.

[0026] At the end of the side surface 20 connected to the end 18a of the front surface 18, an upper flap 86 having a shape symmetrical to the upper flap 62 is provided, separated by a fold line 88. The upper flap 86 has the fold line 88 as its lower base, and the upper base parallel to the fold line 88 is the end 86a. The end 86b of the upper flap 86, which is continuous with the side edge 20a on the opposite side to the fold line 30 of the side surface 20, is formed as a straight line positioned at about 45° to the fold line 88. At the center of the upper flap 86, a through hole 68 is formed as an engagement portion into which the engagement piece 48 of the fold-back piece 40 is inserted in the assembled state. The through hole 68 is formed through the thickness of the upper flap 62, has a semicircular shape, and is surrounded by a straight portion parallel to the side edge 20a and a curved portion bulging toward the extension line of the fold line 30.

[0027] At the end of the lateral surface 20 opposite the fold line 88 is a generally triangular bottom flap 90 bounded by a fold line 92 .

[0028] Next, an example of a method for assembling the packaging box 10 of this embodiment will be described. Note that Fig. 2 shows the front surface of the box-body forming piece 12 of the packaging box 10, and a folding method in which the front surface of the box-body forming piece 12 becomes convex is called a forward folding, and a folding method in which the back surface becomes convex is called a reverse folding.

[0029] First, glue 94 is applied to the backside of the pair of folded pieces 40. The glue 94 is applied between the weakened line 44 and the end 40c, near the side edge 40a. The pair of fold lines 42 are folded forward, and the folded pieces 40 are glued to the backside of the top cover piece 32 as shown in FIG. 3. At this time, the folded pieces 40 are separated from the top flap 62 at the separation cut line 66. FIG. 3 is a view of the backside of the box-forming piece 12 so that the assembly process can be seen. Next, the fold lines 54, 72, 76, 92 are folded forward, and further the fold lines 58, 80 are folded backward, and glue 96 is applied to the backside of the bottom glued pieces 56, 78, and glue 98 is also applied to the front side of the glued piece 22.

[0030] Next, fold line 26 is folded forward, and then fold line 30 is folded forward. As a result, the back surface of bottom adhesive piece 56 is glued to the front surface of bottom flap 70, the back surface of bottom adhesive piece 78 is glued to the front surface of bottom flap 90, and the front surface of adhesive piece 22 is glued to the back surface of side surface 20. As a result, box-forming piece 12 is in a folded state, and in this state, packaging box 10 folded by box-forming piece 12 is shipped to a factory where the contents, which are the merchandise, are packaged. The order of gluing and folding may be other than that described above.

[0031] Next, in a factory where the contents are stored and packaged, the fold lines 24, 26, 28, 30 are folded at 90 degrees each to form a rectangular box. At this time, since the bottom glued piece 56 of the first bottom piece 52 is glued to the bottom flap 70, and the bottom glued piece 78 of the second bottom piece 74 is glued to the bottom flap 90, the fold lines 54, 72, 76, 92 that were folded in half are automatically pulled up and opened at approximately 90 degrees, forming the bottom with a single touch. Then, the first bottom piece insertion piece 60 is inserted into and overlaps the back surface of the second bottom piece 74, and the second bottom piece insertion piece 82 is inserted into and overlaps the back surface of the first bottom piece 52, and they are locked together. When the fold lines 54, 72, 76, and 92 are raised, the side edge 60a of the first bottom piece insertion piece 60 is folded at an obtuse angle by the fold line 61, and the side edge 82a of the second bottom piece insertion piece 82 is folded at an obtuse angle by the fold line 84, so that they do not interfere with the raising and can be assembled smoothly while sliding against each other. This reliably locks the bottom, maintains the shape of the bottom of the box, and prevents it from returning to its folded state, resulting in the assembled state shown in Figure 1(a).

[0032] Then, the top flaps 62, 86 are folded forward at 90° along the fold lines 64, 88, respectively, and the top cover piece 32 is folded forward at 90° along the fold line 34. At this time, as shown in FIG. 1(b), the top cover piece 32 and the pair of fold-back pieces 40 glued to the top cover piece 32 are each folded with the weakened lines 44 as hinges. The top cover piece 32 is folded backward, and the fold-back piece 40 is folded forward. Then, the cutting line 46 of the fold-back piece 40 opens, and the locking piece 48 is raised so as to be flush with the part of the end 40c side of the fold-back piece 40, that is, the locking piece 48 is raised so as to be flush with the part of the top cover piece 32 opposite the back surface 14, and each protrudes outward from the weakened lines 44.

[0033] In this state, the vicinity of the weakened line 44, which is the hinge of the top cover piece 32, is pressed against the top flaps 62, 86, and the locking piece 48 is inserted into the through hole 68 of the top flaps 62, 86 overlapping the back surface of the top cover piece 32. Then, the fold of the weakened line 44 is returned to its original state to make the top cover piece 32 flat, and the insertion piece 36 is folded 90° along the fold line 38 and inserted along the back surface of the front surface 18.

[0034] 1(c), the top cover piece 32 closes the open end of the rectangular box, sealing it and completing the packaging. The top cover piece 32 tries to bulge outward due to the elasticity of the sheet, but the locking piece 48 located near the middle of the fold line 42 on the back side of the top cover piece 32 is locked into the through hole 68 of the top flaps 62, 86, so the top cover piece 32 does not separate from the top flaps 62, 86 and does not bulge outward, remaining flat. The top cover piece 32 and the top flaps 62, 86 are then overlapped with no gaps to close the box.

[0035] When using the product contained in the packaging box 10, the insertion piece 36 is pulled up to open the top cover piece 32. The locking piece 48 is pulled out of the through hole 68, and the engagement is released, allowing the box to be easily opened.

[0036] According to the packaging box 10 of this embodiment, the structure is simple, and it reliably prevents the intrusion of foreign matter and has a high tamper-proof effect. The fold-back piece 40 that folds back on the back surface of the top cover piece 32 is provided with a locking piece 48, and a pair of upper flaps 62, 86 that are overlapped on the back surface of the top cover piece 32 are provided with through holes 68, and the locking piece 48 can be inserted into the through holes 68 to easily lock. When the top cover piece 32 is closed, the top cover piece 32 is slightly elastically deformed and tries to bend outward, but the locking piece 48 is locked into the through holes 68 of the upper flaps 62, 86, so that the top cover piece 32 becomes flat and can be overlapped and closed without any gap between the flaps. This prevents the intrusion of foreign matter through the gaps on both sides of the top cover piece 32. The locking piece 48 can be protruded by simply folding the top cover piece 32 at the weakened line 44, and the locking operation is easy. Since the locking piece 48 is not visible from the surface of the top cover piece 32, the appearance is neat when the top cover piece 32 is closed, making it easy to express in print. The top cover piece 32 is thicker because the fold-back piece 40 is folded back, making it possible to reduce gaps. The top cover piece 32 has the same shape and area as the opening of the box, so a sufficient area of ​​overlap can be provided for the top flaps 62, 86, which is more effective at preventing the intrusion of foreign matter.

[0037] Next, a second embodiment of the present invention will be described with reference to Figures 5 and 6. Here, the same members as those in the above embodiment are given the same reference numerals and the description will be omitted. The packaging box 100 of this embodiment is provided by assembling box-body forming pieces 102 formed by punching a paper sheet. Figure 6 is a development view of the box-body forming pieces 102 as seen from the front, and the box-body forming pieces 102 are formed by connecting a rectangular back surface 14, a side surface 16, a front surface 18, and a side surface 20 in parallel to each other in this order.

[0038] A rectangular top cover piece 32 is provided at one end of the back surface 14, separated by a fold line 34. An insertion piece 36 is provided at the end of the top cover piece 32 opposite the fold line 34, separated by a fold line 38. A weakened line 44 is provided parallel to the fold lines 34 and 38, passing near the center of the top cover piece 32, and the weakened line 44 is connected to a pair of side edges of the top cover piece 32 that are positioned approximately perpendicular to the fold line 34. A cut line 104 is provided along the weakened line 44 near a pair of side edges of the top cover piece 32 that are positioned approximately perpendicular to the fold line 34.

[0039] The cutting line 104 is formed in a trapezoidal shape protruding toward the fold line 34, both ends of the cutting line 104 are continuous with the weakened line 44, the middle part of the cutting line 104 is located closer to the fold line 34 than the weakened line 44, and the inside part of the cutting line 104 is not provided with the weakened line 44. When the top cover piece 32 is folded using the weakened line 44 as a hinge, the inside of the cutting line 104 becomes a locking piece 106 that protrudes flush with the part of the top cover piece 32 on the insertion piece 36 side. The cutting line 104 and the locking piece 106 are provided near a pair of side edges that are positioned approximately perpendicular to the fold line 34 of the top cover piece 32, one each.

[0040] A trapezoidal upper flap 108 is provided at the end of the side surface 16 that is connected to the fold line 34 of the back surface 14, separated by a fold line 110. A fold-back line 112 that passes through the center of the upper flap 108 and is approximately parallel to the fold line 110 is provided. Between the end 108a of the upper flap 108 opposite the fold line 110 and the fold-back line 112, a through hole 68 that is an engagement portion into which the engagement piece 106 of the upper cover piece 32 is inserted in the assembled state is formed through the thickness. The through hole 68 is semicircular and is surrounded by a straight portion parallel to the fold line 26 and a curved portion that bulges toward the extension line of the fold line 28. The length of the through hole 68 in the direction parallel to the fold line 26 is slightly longer than the length of the engagement piece 106 in the direction perpendicular to the fold line 26.

[0041] At the end of the lateral surface 20 connected to the end 18a of the front surface 18, an upper flap 114 having a shape symmetrical to the upper flap 108 is provided, separated by a fold line 116. A fold-back line 118 is provided passing near the center of the upper flap 114 and approximately parallel to the fold line 116. A through hole 68, which is an engagement portion into which the engagement piece 106 of the upper cover piece 32 is inserted in the assembled state, is formed between the end 114a of the upper flap 114 opposite to the fold line 116 and the fold-back line 118, penetrating the thickness. The through hole 68 is semicircular and is formed by being surrounded by a straight portion parallel to the side edge portion 20a and a curved portion bulging toward the extension line of the fold line 30.

[0042] Next, an example of a method for assembling the packaging box 100 of this embodiment will be described. Note that Fig. 6 shows the front surface of the box-body forming piece 102 of the packaging box 100, and a folding method in which the front surface of the box-body forming piece 102 is convex is called a forward folding, and a folding method in which the back surface is convex is called a reverse folding.

[0043] First, the fold lines 54, 72, 76, and 92 are folded forward, and then the fold lines 58 and 80 are folded backward, and glue 96 is applied to the backsides of the bottom glued pieces 56 and 78, and glue 98 is also applied to the front side of the glued piece 22. Next, the fold line 26 is folded forward, and then the fold line 30 is folded forward. As a result, the box-forming piece 102 is in a folded state, and in this state, the packaging box 100 folded by the box-forming piece 102 is shipped to a factory where the contents, which are the merchandise, are packaged. The order of gluing and folding may be other than that described above.

[0044] Next, in a factory where the contents are stored and packaged, the fold lines 24, 26, 28, and 30 are folded forward at 90° to form a rectangular box, resulting in the assembled state shown in FIG. 5(a). Then, the top flaps 108 and 114 are folded forward at 90° along the fold lines 110 and 116, respectively, and then folded backward at 180° along the fold lines 112 and 118. The fold lines 112 and 118 of the top flaps 108 and 114 tend to open due to the elasticity of the sheet, causing the ends 108a and 114a to rise slightly above the folded fold lines 110 and 116. Next, the top cover piece 32 is folded forward at 90° along the fold line 34. This prevents the ends 108a and 114a from rising slightly above the fold lines 110 and 116. At this time, as shown in Fig. 5(b), the upper cover piece 32 is folded back using the weakened lines 44 as hinges. Then, the pair of cutting lines 104 opens, and the locking pieces 106 are raised so as to be flush with the part of the upper cover piece 32 on the insertion piece 36 side, and each protrudes outward from the weakened lines 44.

[0045] In this state, the vicinity of the weakened line 44, which is the hinge of the top cover piece 32, is pressed against the top flaps 108, 114, and the locking piece 106 is inserted into the through hole 68 of the top flaps 108, 114 overlapping the back surface of the top cover piece 32. Then, the fold of the weakened line 44 is returned to its original state to make the top cover piece 32 flat, and the insertion piece 36 is folded 90° along the fold line 38 and inserted along the back surface of the front surface 18.

[0046] As a result, the package is sealed and the packaging is completed as shown in Fig. 5(c). The top cover piece 32 tries to bulge outward due to the elasticity of the sheet, but the locking pieces 106 located near the middle of both side edges of the top cover piece 32 are locked into the through holes 68 of the top flaps 108, 114, so the top cover piece 32 does not bulge outward away from the top flaps 108, 114 and remains flat. The top flaps 108, 114 are folded in half at the fold lines 112, 118 and are pressed against the back surface of the top cover piece 32 due to the elasticity of the sheet, so there is no gap between the top cover piece 32 and the top flaps 108, 114.

[0047] When using the product stored in the packaging box 100, the insertion piece 36 is pulled up to open the top cover piece 32, as in the above embodiment. The locking piece 106 is pulled out of the through hole 68, disengaged, and the box can be easily opened.

[0048] The packaging box 100 of this embodiment has the same effect as the above embodiment. The upper flaps 108, 114 are folded in half at the fold lines 112, 118, and are pressed against the back surface of the upper cover piece 32 by the elasticity of the sheet, so that there is no gap between the upper cover piece 32 and the upper flaps 108, 114, and it is possible to more reliably prevent the intrusion of foreign matter. Since the upper cover piece 32 is provided with the locking piece 106, when the upper cover piece 32 is folded at the weakened line 44, the locking piece 106 can be easily protruded, making the locking operation easy. The locked state can be confirmed from the surface of the upper cover piece 32, and there is also an effect of preventing tampering.

[0049] Next, a third embodiment of the present invention will be described with reference to Figures 7 and 8. Here, the same members as those in the above embodiment are given the same reference numerals and the description will be omitted. The packaging box 120 of this embodiment is provided by assembling box body forming pieces 122 formed by punching a paper sheet. Figure 8 is a development view of the box body forming pieces 122 as seen from the front, and the box body forming pieces 122 are formed by connecting a rectangular back surface 14, a side surface 16, a front surface 18, and a side surface 20 in parallel to each other in this order.

[0050] A rectangular top cover piece 32 is provided at one end of the back surface 14, separated by a fold line 34. An insertion piece 36 is provided at the end of the top cover piece 32 opposite the fold line 34, separated by a fold line 38. A weakened line 44 is provided passing near the center of the top cover piece 32 and parallel to the fold line 34 and the fold line 38. The weakened line 44 communicates with a pair of side edges positioned approximately perpendicular to the fold line 34 of the top cover piece 32, and a notch 124 recessed in a V shape toward the center of the top cover piece 32 is provided at the side edge coinciding with the weakened line 44.

[0051] The side edge of the cutout 124 close to the fold line 34 is positioned at an angle relative to the weakened line 44, and this side edge close to the fold line 34 is provided with a semicircular locking piece 126 that bulges outward. When the top cover piece 32 is folded at the weakened line 44, the locking piece 126 protrudes flush with the portion of the top cover piece 32 on the fold line 34 side. The side edge of the cutout 124 opposite the locking piece 126 and close to the insertion piece 36 is formed as a straight line that intersects at an angle relative to the weakened line 44. The cutout 124 and the locking piece 126 are provided on both side edges of the top cover piece 32, respectively.

[0052] At the end of the side surface 16 that is connected to the fold line 34 of the back surface 14, a deformed hexagonal top flap 128 is provided, separated by a fold line 130. The top flap 128 is provided with a cut line 132, which is an engagement portion into which the engagement piece 126 of the top cover piece 32 is inserted in the assembled state. The cut line 132 is formed as a short straight line that continues to the fold line 130, and one end of the cut line 132 continues to a position slightly closer to the fold line 26 than the middle of the fold line 130, and the opposite end reaches a position slightly away from the fold line 130 and also slightly away from the extension line of the fold line 26, and the cut line 132 is inclined so as to move away from the extension line of the fold line 26 as it moves away from the fold line 130. The length of the cut line 132 is slightly longer than the width that intersects with the protruding direction of the engagement piece 126. Auxiliary cut lines 134 are provided at the ends and middle of the cut lines 132 at right angles to the cut lines 132, and each auxiliary cut line 134 is formed extending obliquely in the opposite direction to the fold lines 130, making it easier to insert the locking pieces 126 into the cut lines 132 from the opposite direction to the fold lines 130.

[0053] At the end of the lateral surface 20 that is connected to the end 18a of the front surface 18, an upper flap 136 that is symmetrical to the upper flap 128 is provided, separated by a fold line 138. The upper flap 136 is provided with a cut line 132 that is an engagement portion into which the engagement piece 126 of the upper cover piece 32 is inserted in the assembled state. One end of the cut line 132 continues to a position slightly closer to the side edge 20a than the middle of the fold line 138, and the opposite end reaches a position slightly away from the fold line 138 and also slightly away from the extension line of the side edge 20a, and the cut line 132 is inclined so as to move away from the extension line of the side edge 20a as it moves away from the fold line 138. Auxiliary cut lines 134 that are perpendicular to the cut line 132 are provided at the end and middle of the cut line 132.

[0054] Next, an example of a method for assembling the packaging box 120 of this embodiment will be described. Note that Fig. 8 shows the front surface of the box-body forming piece 122 of the packaging box 120, and a folding method in which the front surface of the box-body forming piece 122 becomes convex is called a forward folding, and a folding method in which the back surface becomes convex is called a reverse folding.

[0055] First, as in the above embodiment, the fold lines 54, 72, 76, 92 are folded forward, and then the fold lines 58, 80 are folded backward, and glue 96 is applied to the backsides of the bottom glued pieces 56, 78, and glue 98 is also applied to the front side of the glued piece 22. Next, the fold line 26 is folded forward, and then the fold line 30 is folded forward. As a result, the box-forming piece 122 is in a folded state, and in this state, the packaging box 120 folded by the box-forming piece 122 is shipped to a factory where the contents, which are the merchandise, are packaged. The order of gluing and folding may be other than that described above.

[0056] Next, in a factory where the contents are stored and packaged, the fold lines 24, 26, 28, and 30 are each folded at 90° to form a rectangular box, resulting in the assembled state shown in FIG. 7(a).

[0057] Then, the top flaps 128, 136 are folded 90° forward along the fold lines 130, 138, respectively, and then the top cover piece 32 is folded 90° forward along the fold line 34. At this time, as shown in Fig. 7(b), the top cover piece 32 is folded backward along the weakened line 44, so that the pair of locking pieces 126 are flush with the part of the top cover piece 32 on the fold line 34 side, and both ends of the weakened line 44 form corners.

[0058] In this state, when the locking piece 126 together with the top cover piece 32 is lightly pressed from above against the cut line 132 of the top flaps 128, 136, the top flaps 128, 136 are slightly elastically deformed and sink toward the inside of the box body, the auxiliary cut line 134 of the cut line 132 is opened, and the locking piece 126 is inserted into the cut line 132. Then, the weakened line 44 is returned to its original state to make the top cover piece 32 flat, and the insertion piece 36 is folded 90° forward along the fold line 38 and inserted along the back surface of the front surface 18.

[0059] As a result, the sealed state is achieved as shown in Fig. 7(c), and packaging is completed. The top cover piece 32 tries to bulge outward due to the elasticity of the sheet, but the locking pieces 126 located near the middle of both side edges of the top cover piece 32 are locked to the cut lines 132 of the top flaps 128, 136, so the top cover piece 32 does not separate from the top flaps 128, 136 and bulges outward, and remains flat. In addition, because the locking pieces 126 are provided continuously on both side edges of the top cover piece 32, the top cover piece 32 and the top flaps 128, 136 can be overlapped and closed without any gaps.

[0060] The packaging box 120 of this embodiment has the same effects as the above embodiment. It also has a simple structure and is easy to assemble. The locking piece 126 can be protruded by simply bending the top cover piece 32 lightly at a small angle along the weakened line 44, making the locking operation easy. The locked state can be confirmed from the outside of the top cover piece 32, and there is also an effect of preventing tampering.

[0061] The present invention is not limited to the above embodiment, and the shape and number of the locking pieces and locking parts can be changed as appropriate as long as they can be securely locked to each other, and the number of locking pieces and locking parts provided on one packaging box may be three or more. The curved cutting line may be a bent cutting line, and any other line may be used as long as the locking pieces can be formed.

[0062] The weakening lines may be any lines that make it easier to fold the lid, such as pressed creases, fold lines, half-cut lines, or break lines. The box can be used for various items as storage objects, and the size and shape of the box can be changed as appropriate according to the size of the storage objects and the number of items to be stored. The material of the box-forming pieces can be freely selected from synthetic resins and laminated synthetic resins and paper in addition to paper. The number and length of the fold lines and auxiliary cut lines can also be changed as appropriate, and the fold lines may be provided as break lines or the like to make them easier to fold. The structure of the bottom can be freely changed. The bottom may be provided with a lid with a locking piece and a flap with a locking part, and in this case, since the lid is flat, it is difficult for the lid to fall over when displayed on the bottom surface. [Explanation of symbols]

[0063] 10,100,120 Packaging boxes 12,102,122 Box forming piece 14 Back 16,20 Side 18 Front 22 Glued strip 32 Top cover piece 40 Folded piece 44 Weakened Line 46,104 cutting line 48,106,126 Locking piece 62,86,108,114,128,136 Upper flap 68 Through hole 124 Notch

Claims

1. The box-forming piece is provided with a plurality of side walls assembled to a cylinder, a lid piece continuous with one of the side walls and closing one open end of the cylinder, and a pair of flaps continuous with a pair of side walls located on both sides of the side wall on which the lid piece is provided and overlapping the back surface of the lid piece, the lid piece is provided with a weakened line by which the lid piece can be folded and a locking piece located near the weakened line, and the pair of flaps are each provided with a locking portion into which the locking piece is inserted for locking, When closing the open end of the cylindrical body with the lid piece, by folding the lid piece at the weakened line, the locking piece protrudes near the weakened line, and the protruding locking piece is inserted into the locking portion of the flap, In a sealed state, the lid piece is overlapped with the pair of flaps to close one open end of the cylindrical body, and the locking piece is locked to the locking portion of the flap, A packaging box characterized in that a fold-back piece is provided on the side edge of the lid piece so as to fold over the back surface of the lid piece and face the back surface, the fold-back piece is provided with the weakened line continuing from the lid piece, and the locking piece is provided in the vicinity of the weakened line of the fold-back piece.

2. A packaging box as described in claim 1, wherein the fold-over piece is glued to the back surface of the lid piece.

3. A box-forming piece is provided with a number of side walls assembled to a cylindrical body, a lid piece continuous with one of the side walls and closing one open end of the cylindrical body, and a pair of flaps continuous with a pair of side walls located on either side of the side wall on which the lid piece is provided and overlapping the back surface of the lid piece, the lid piece is provided with a weakened line by which the lid piece can be folded and a locking piece located in the vicinity of the weakened line, and the pair of flaps are each provided with a locking portion into which the locking piece is inserted to lock; When closing the open end of the cylindrical body with the lid piece, by folding the lid piece at the weakened line, the locking piece protrudes near the weakened line, and the protruding locking piece is inserted into the locking portion of the flap, In a sealed state, the lid piece is overlapped with the pair of flaps to close one open end of the cylindrical body, and the locking piece is locked to the locking portion of the flap, A packaging box characterized in that a fold line is provided on the pair of flaps, the locking portion is provided between the fold line and the end of the flap, and the locking piece is locked to the locking portion when the flap is folded in half at the fold line.

4. 4. The packaging box according to claim 3, wherein the weakened line passes near the center of the lid piece and extends in a direction extending approximately parallel to the boundary between the lid piece and the side wall, and the locking pieces are provided on both sides of the center of the lid piece.

5. A box-forming piece is provided with a number of side walls assembled to a cylindrical body, a lid piece continuous with one of the side walls and closing one open end of the cylindrical body, and a pair of flaps continuous with a pair of side walls located on either side of the side wall on which the lid piece is provided and overlapping the back surface of the lid piece, the lid piece is provided with a weakened line by which the lid piece can be folded and a locking piece located in the vicinity of the weakened line, and the pair of flaps are each provided with a locking portion into which the locking piece is inserted to lock; When closing the open end of the cylindrical body with the lid piece, by folding the lid piece at the weakened line, the locking piece protrudes near the weakened line, and the protruding locking piece is inserted into the locking portion of the flap, In a sealed state, the lid piece is overlapped with the pair of flaps to close one open end of the cylindrical body, and the locking piece is locked to the locking portion of the flap, The weakened lines are provided to reach both side edges of the lid piece, and the side edges of the lid piece along the weakened lines are provided with a V-shaped notch that is recessed toward the center of the lid piece, and the locking piece is formed on the side edge of the V-shaped notch that is closest to the side wall.

6. A packaging box as described in claims 1 to 5, wherein a curved or bent cutting line is provided along the weakened line, both ends of the cutting line are continuous with the weakened line, a middle portion of the cutting line is located closer to the side wall on which the lid piece is provided than the weakened line, an inner portion of the cutting line is not provided with the weakened line, and the inner side of the cutting line becomes the engaging piece that protrudes from the lid piece when the lid piece is folded at the weakened line.

7. 6. The packaging box according to claim 1, wherein the engaging portion is a through hole or a cut line penetrating the thickness of the flap.

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