JPH08156930A - Bottom locking type packaging box - Google Patents

Abstract

PURPOSE: To provide a bottom locking type packaging box wherein the bottom part is formed being almost flat, the load resistance is high, and the building up and folding are easy. CONSTITUTION: First flaps 7, 8 are provided on first side plates 2, 3, and second flaps 9, 10 are provided on second side plates 4, 5. Extension parts 19, 23 are provided on the first flaps 7, 8, and fluctuating parts 19b, 23b which fluctuate by a first folding line for escape are provided on the extension parts 19, 23. Free pieces 22, 24 which can fluctuate by a second folding line 26 for escape, etc., are provided on the fluctuating parts 19b, 23b. When a square cylindrical body part 27 is formed of the first side plates 2, 3 and second side plates 4, 5, the first flaps 7, 8 and second flaps 9, 10 tilt while the fluctuating parts 19b, 23b and free pieces 22, 24 fluctuate in the separating direction from each other, and a closed bottom part 26 is formed. The internal surface side of the bottom part 26 is covered flatly with the first flaps 7, 8 which overlap each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom lock type packaging box in which a bottom is formed at the same time when a body is formed during use.

[0002]

2. Description of the Related Art Conventionally, a packaging box 30 called a bottom lock type corrugated cardboard box is known as shown in FIGS. 6 (a) and 6 (b) showing the shape of the bottom. As shown in FIG. 7, this type of packaging box 30 is formed by assembling a plate material 30 ′ formed by punching a rectangular corrugated paperboard. If the structure of the plate member 30 'is described in detail, the first side plates 31, 3
2 and the second side plates 33, 34 are alternately connected to each other through the fold lines m, n, o, and the upper edge of each side plate 31, 32, 33, 34 has four fold lines p. The top flap 60 is provided with bottom flaps 35, 36, 37, and 38 connected to the lower end edges of the side plates 31, 32, 33, and 34 via fold lines q, respectively.

Bottom flaps 35, 36, 37, 38
Is composed of a pair of first flaps 35, 36 connected to the first side plates 31, 32, and a pair of second flaps 37, 38 connected to the second side plates 33, 34. . The first flaps 35, 36 are both formed in the same shape, and are provided with a substantially triangular adhesive piece 39 on one side thereof through a fold line r. The adhesive piece 39 is adhered to the outer surface of each of the second flaps 37 and 38. The fold line r is provided so as to be inclined at an angle of 45 ° with respect to the fold line q at the lower edge of each side plate 31, 32, 33, 34. Also,
A V-shaped notch 40 is formed at the center of the front ends of the first flaps 35 and 36, and a corner 41 of the notch 40 is located substantially at the center of the bottom.

When manufacturing a packaging box from the plate material 30 'thus formed, first, the side plates 31, 32, 3 are formed.
The flaps 35, 36, 37, 38 at the lower end edges of 3, 34 are folded back along the fold line q, and the side plates 31, 32, 3 are respectively folded.
Polymerizes on the inner surface side of 3,34. Then, the first flap 3
The adhesive pieces 39 of 5 and 36 are folded back to the outer surface sides of the first flaps 35 and 36 through the fold lines r to be polymerized. An adhesive is applied to the exposed surface of the adhesive piece 39, and then the first side plate 31 located at one end is folded back onto the second side plate 33 adjacent to the first side plate 31 through the fold line m, and the other end is provided. The positioned second side plate 34 is folded back onto the first side plate 32 adjacent to the second side plate 34 through the fold line o. As a result, the adhesive pieces 39 of the first flaps 35, 36 are made to adhere to the second flaps 37, 3 respectively.
Adhered to 8. At the same time, an adhesive is applied to the adhesive piece 42 that is continuously provided on the side edge of the first side plate 31, and the adhesive piece 42 is attached to the second piece.
Adhesive to the edge of the side plate 34.

Then, each side plate 31, 32, 33, 34
Are spread in the directions away from each other to form a rectangular tube to form a body portion, so that the flaps 35, 36, 37, 38 are attached to the side plates 31, 32, 3 via the fold line q.
Located at a right angle to the first and second flaps 35 and 3
The fold line r of the adhesive piece 39 of No. 6 spreads horizontally, and
As shown in FIG. 6A showing the inside state and FIG. 6B showing the outside state (bottom view), bottom portions for closing the side plates 31, 32, 33, 34 are formed. Each flap 35, 36, 3
When 7, 38 are horizontal, the first flaps 35, 36
The V-shaped notches 40 are engaged with each other to maintain the closed state.

As described above, this type of packaging box is extremely easy to assemble in a flatly folded state with the flaps 35, 36, 37, 38 at the bottom already bonded at the manufacturing stage. And, at the time of use, each side plate 31, 32, 3
The closed bottom portion 43 can be easily formed by following the formation of the body portion of the rectangular tube by 3, 34, and it can be folded flat again after use. However, as shown in FIG. 6A, each flap 3 is attached to the bottom portion 43.
Since a relatively large number of overlapping steps 44 are formed by 5, 36, 37, and 38, there is a disadvantage that the stability when storing an article is poor. Therefore, a plate member having the same shape as that of the bottom portion 43 is used for
Although it is laid on the surface 3 to be flat, the work is troublesome, and there is a disadvantage that a plate material to be laid on the bottom portion 43 must be prepared separately.

Therefore, in order to make the bottom 43 flat without laying the plate on the bottom 43, it is conceivable that one of the four flaps forming the bottom has the role of the plate. That is, in the packaging box 46 showing the structure of the bottom portion 45 in FIGS. 8A and 8B, and explaining the unfolded state, as shown in FIG. 9, the first side plates 47, 48 in the plate member 46 ′,
The second side plates 49, 50 are continuously provided via the fold lines s, t, u, and the bottom flaps 51, 52, 53 are provided at the lower end edges of the side plates 47, 48, 49, 50 via the fold lines v. , 54
However, they are arranged in series.

Bottom flaps 51, 52, 53, 54
Is composed of a pair of first flaps 51, 52 connected to the first side plates 47, 48 and a pair of second flaps 53, 54 connected to the second side plates 49, 50. . At this time, one of the second flaps 53 serves as a substitute for the above-mentioned plate material and is used as each side plate 47, 48, 49, 50.
It has a shape corresponding to the bottom when the body is formed and is formed relatively large. Moreover, the respective second side plates 49, 50 in which the second flaps 53, 54 are arranged in series are the first side plates 47, 4 in which the first flaps 51, 52 are arranged in series.
The width dimension is larger than 8 and therefore the second flap 5
The shapes of 3, 54 are larger than those of the first flaps 51, 52.

Each of the first flaps 51, 52 is provided with a substantially triangular adhesive piece 55 on one side thereof along a fold line x. The adhesive piece 55 is adhered to the outer surface of each of the second flaps 53 and 54. The fold lines x are the side plates 47, 48, 49,
The lower edge of 50 is inclined at an angle of 45 ° with respect to the fold line v.

When a packaging box is manufactured from the plate member 46 'thus formed, as described above, the side plates 47,
Flaps 51, 52, 5 on the lower edges of 48, 49, 50
3, 54 are folded back along the crease line v, and the side plates 47, 4
Polymerize to 8,49,50. Then, the first flap 5
The adhesive pieces 55 of 1, 52 are folded back to the outer surface sides of the first flaps 51, 52 through the fold line x to be polymerized. An adhesive is applied to the exposed surface of the adhesive piece 55, and then the first side on one side is applied.
The side plate 47 is folded back on the second side plate 49 via the fold line s, and the second side plate 50 on the other side is folded back on the first side plate 48 via the fold line u. Thereby, the first flaps 51, 5
Two adhesive pieces 55 are adhered to each second flap 53, 54. At the same time, the adhesive piece 5 continuously provided on the side edge of the first side plate 47.
An adhesive agent is applied to 6, and the adhesive piece 56 is adhered to the edge portion of the second side plate 50.

Then, as shown in FIG. 10, each side plate 4
The flaps 51, 52, 53, and 54 are connected to the side plates 47 via the fold line v by expanding 7, 48, 49, and 50 in the directions away from each other so as to form a square tube to form the body portion. , 48, 49, 50, and the fold line x of the adhesive piece 55 of the first flaps 51, 52 spreads horizontally to form a bottom portion closing each side plate 47, 48, 49, 50. It At this time, the second flap 53 covers the upper surface of the bottom, and the bottom is formed flat. The second
When the side plates 47, 48, 49, 50 are spread in directions away from each other, the flap 53 moves in the falling direction while sliding one side edge thereof against the inner surface of the first side plate 47, and therefore does not hinder the movement thereof. As described above, the inclined portion 57 in which one side edge of the second flap 53 is inclined and cut out is formed. The second flap 53 is formed to be larger than the first flaps 51, 52 in order to form the inclined portion 57 that is smoothly slidably contacted along the first side plate 47 when the second flap 53 tilts. This is because it is possible to reduce the area where a part of the second flap 53 is cut out. For example, when the first flap 51 is formed larger than the second flap 53, it is necessary to form an inclined portion. This is because the area of notching the part becomes large, and the first flap 51 cannot have a size sufficient to replace the plate material.

As described above, each side plate 47, 48, 49, 5
When the body is formed by 0, the bottom is formed, and at the same time, the second flap 53 on one side covers the bottom and is made flat, so that it is not necessary to prepare the plate material or the like, and the assembling of the packaging box is extremely easy. Has become.

However, in the above structure, the second flap 5 is
3 has to be formed in a larger shape than the first flaps 51, 52, the first flaps 51, 52
Therefore, the size of the adhesive piece 55 provided on the substrate is relatively small. For this reason, the adhesive strength between the second flaps 53, 54 and the first flaps 51, 52 is low, and there is a possibility that bottoming out may occur depending on the weight of the stored items.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a bottom-lock type packaging box having a substantially flat bottom, high load resistance, and easy to assemble and fold. With the goal.

[0015]

In order to achieve the above object, the present invention provides a pair of square first side plates and a pair of square second side plates alternately in one direction via fold lines. A pair of first flaps, which are arranged, are continuously provided to the lower end edges of the respective first side plates via folding lines, and are folded back to the inner surface side of the first side plates by the folding lines, and the second flaps of the second side plates. Each of the lower end edges is continuously provided via a crease line, and each crease line causes each second
And a pair of second flaps that are folded back and overlapped with each other on the inner surface of the side plate, and the first flap has an angle of 45 ° from one end of the lower end edge of the second side plate to the lower end edge of the second side plate. Then, they are continuously provided through a fold line extending to the leading edge of the first flap, and an adhesive piece that is folded back and polymerized is provided on the outer surface side of the first flap by the fold line, and the adhesive piece is positioned on one side. A second side plate adjacent to the first side plate by a crease line
A first side plate that is folded back onto the inner surface side of the side plate and adheres the adhesive piece to the outer surface side of the second flap via an adhesive agent, and a second side plate located on the other side is adjacent to the second side plate by a fold line. While being folded back and polymerized to the inner surface side of the second flap, the adhesive piece is adhered to the outer surface side of the second flap with an adhesive agent, and the first side plate and the second side plate are positioned at right angles to each other via fold lines. When unfolded to form a square tubular body,
A packaging box in which a closed bottom is formed at a right angle to each first side plate and each second side plate in a state where each second flap and each first flap are connected by each adhesive piece, The first flap overlaps with the inner surface of the other second flap that faces the second flap connected by the adhesive piece, and the other first side plate that faces the first side plate in which the first flap is connected. An extension portion having a tip edge that abuts a lower end edge of the extension portion, and an oscillating portion that is swingable via an escape fold line extending from the tip edge of the extension portion toward the center of the first flap. It is characterized by

Further, it is preferable that an oscillating piece which can be oscillated is continuously provided on the inner side edge of the oscillating portion through another escape fold line.

[0017]

According to the present invention, each of the first flaps is provided with the extending portion and the swinging portion. When the pair of first flaps form the bottom portion, the respective extending portions and the swinging portions cover the second flap exposed inside the box to be flat. Further, since the outer surface side of the second flap is supported by the half portion of the one first flap and the inner surface side is covered by the half portion of the other first flap, the second flap covers a relatively large area between the pair of first flaps. Since the adhesive piece is provided in a relatively wide area of the first flap, the adhesive strength between the first flap and the second flap is improved and the load resistance is improved.

The packaging box of the present invention, when manufactured,
One first side plate is overlapped with one second side plate, and the other second side plate is overlapped with the other first side plate and is flatly folded,
Each flap is stored on the inner surface side of each side plate. Then, when the article is stored, the body is formed so that each side plate has a square tubular shape. In the process of forming each side plate into a rectangular tube shape, when the first side plate is spread from the adjacent second side plate at the fold line as a boundary, the adhesive piece in the overlapping state on the first flap separates from the first flap. When the first flap is tilted and positioned horizontally,
The first flap and the adhesive piece together form a plane. Since the second flap is adhered to the adhesive piece, the first flap is positioned horizontally and at the same time the second flap is positioned horizontally. Here, the pair of first flaps and the pair of second flaps are tilted in a direction in which they come into contact with each other on the inner surface side of each side plate to form a bottom portion, but the pair of first flaps are both provided with the extending portion. Therefore, before the both first flaps become horizontal, the two extending portions come into contact with each other to prevent tilting of the both first flaps. Therefore, a direction in which the escape fold line is provided in the extending part and a part of the extending part is made to be an oscillating part so that the oscillating parts in which the oscillating parts contact each other are separated from each other By swinging the first flap, the first flaps can be smoothly tilted. When both the first flaps are horizontal, the extending portion and the swinging portion form one plane.

Further, a swingable swingable piece is continuously provided on the inner side edge of the swingable portion via another escape fold line, so that the inner surface of the bottom portion covers a wider area. , The strength of the bottom portion is improved and the inner surface side of the bottom portion is formed flat. When the body is formed so that each side plate is in the shape of a square cylinder, both first flaps tilt and the loose pieces come into contact with each other, but both loose pieces separate the other escape fold lines. The first and second flaps are swung through to smoothly tilt both first flaps. After that, when both the first flaps are horizontal, the extending portion, the swinging portion, and the loose piece all form a plane.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a plan view of the packaging box of the present embodiment with the upper portion cut off, and FIG. 1B is a bottom view of the packaging box of the present embodiment.
2 is an exploded view of the packaging box of the present embodiment, FIGS. 3 and 4 are explanatory views showing the assembling process of the packaging box of the present embodiment, and FIG. 5 is a top view of the packaging box of another embodiment of the present invention. It is a top view of the state where it did.

The packaging box 1 of this embodiment is a cardboard box having a bottom structure called a bottom lock type as shown in FIGS. 1 (a) and 1 (b).

The packaging box 1 is formed by assembling a plate material 1'formed by punching a rectangular corrugated cardboard as shown in FIG. In the plate member 1 ', first side plates 2 and 3 and second side plates 4 and 5 are alternately arranged in one direction via fold lines a, b, and c. A top flap 6 is continuously provided on the upper edge of each of the side plates 2, 3, 4, 5 via a fold line d. First side plate 2, 3
The first flaps 7, 8 are attached to the lower edge of the first fold line e, f via fold lines e, f.
Are lined up. Second flaps 9 and 10 are connected to the lower end edges of the second side plates 4 and 5 via fold lines g and h.

The first flaps 7 and 8 are both formed in the same shape, and are provided with substantially triangular adhesive pieces 11 and 12 on one side through fold lines i and j. The adhesive piece 1
1, 12 are adhered to the outer surface of each second flap 9, 10. The fold lines i and j are inclined with respect to the fold lines e and f at the lower edges of the first side plates 2 and 3 at an angle of 45 °. In addition, a part of the adhesive pieces 11 and 12 on the first side plates 2 and 3 side is provided with a cutout portion 13 in order to eliminate the difficulty of bending due to the thickness of the plate material 1 ′ when bending along the fold lines i and j.
14 is formed. Further, V-shaped notches 15 and 16 are formed at the central portions of the tips of the first flaps 7 and 8, and the corners 17 and 18 of the notches 15 and 16 are located substantially at the center of the bottom. .

The first flap 7 on one side is superposed on the inner side surface of the second flap 10 on the other side facing the second flap 9 adjacent to the adhesive piece 11, and the first flap 7 is continuously provided. Further, the extending portion 19 is provided so as to come into contact with the lower end edge (fold line f) of the other first side plate 3 facing the first side plate 2. The extending portion 19 has a tip edge 19a.
From the first flap 7 toward the center of the first flap 7 via a first escape fold line 20. A swingable portion 19b is provided, and a second swingable portion 19b is provided at an inner side edge of the swingable portion 19b. A swingable free piece 22 is continuously provided via a relief fold line 21. A tip edge 22a of the loose piece 22 coincides with a center line in a direction orthogonal to a lower edge (fold line e) of the first side plate 2. Similarly, the other first flap 8 also includes an extending portion 23, a first escape fold line 25, a swinging portion 23b, a second escape fold line 26, and a loose piece 24.

In the case of manufacturing a packaging box from the plate material 1'formed in this way, first, as shown in FIG. 3 (a) in plan view from the inner surface side, the flaps 7, 8, 9, 10 are arranged. Are folded back along fold lines e, f, g, h, and side plates 2,
Polymerizes on the inner surface side of 3, 4, 5. Next, the adhesive pieces 11 and 12 of the first flaps 7 and 8 are folded back to the outer surface side of the first flaps 7 and 8 through the fold lines i and j, respectively, and are polymerized. The adhesive z is applied to the exposed surfaces of the adhesive pieces 11 and 12.

Then, as shown in FIG. 3 (b), the first side plate 2 located at one end is connected to the first side plate 2 through the fold line a.
Is folded back onto the second side plate 4 adjacent to the second side plate 4, and the second side plate 5 located at the other end is folded back onto the first side plate 3 adjacent to the second side plate 5 through the fold line c. As a result, the adhesive pieces 11 and 12 of the first flaps 7 and 8 are adhered to the respective second flaps 9 and 10. At the same time, an adhesive is applied to the adhesive piece 25 that is continuously provided on the side edge of the first side plate 2 via the fold line k, and the adhesive piece 25 is adhered to the inner surface of the edge portion of the second side plate 5. In this manner, the packaging box 1 is extremely easily manufactured in a flatly folded state in which the flaps 7, 8, 9, and 10 forming the bottom portion 26 are already bonded at the manufacturing stage.

At the time of use, as shown in FIG. 1A, the body portion 27 is formed so that the side plates 2, 3, 4, 5 are in the shape of a rectangular tube. In the process of forming each side plate 2, 3, 4, 5 into a rectangular tube shape, the top flap 6 is removed for convenience of description, and each flap 7,
8, 9, and 10 start tilting toward the inside of the body 27. Adhesive piece 1 that was in a polymerized state on the first flaps 7 and 8
1, 12 are expanded in the direction away from the first flaps 7, 8. At this time, the extension portions 1 of both the first flaps 7 and 8
9 and 23 are in contact with each other at the central position of the body 27,
The oscillating portions 19b and 23b bent outward by the first escape fold lines 20 and 25 move in sliding contact with each other, and the first flaps 7 and 8 are smoothly tilted.

As the flaps 7, 8, 9 and 10 are further tilted, the loose pieces 22 and 2 are released as shown in FIG. 4 (b).
The four are brought into contact with each other at the center position of the body portion 27. At this time, the two loose pieces 22 and 24 are separated from each other by the second fold line 2 for escape.
The first flaps 7 and 8 are swung through the rollers 1 and 26, and the first flaps 7 and 8 are smoothly tilted.

As shown in FIG. 1A, when the flaps 7, 8, 9 and 10 are horizontal and the bottom portion 26 is formed, the cutout portions 15 and 16 of the first flaps 7 and 8 have their corners. The first flaps 7 and 8 are maintained in a horizontal state by being locked to each other by the portions 17 and 18,
23, the swinging portions 19b and 23b, and the loose pieces 22 and 24 cover the second flaps 9 and 10 on the inner surface side of the bottom portion 26, and the inner surface side of the bottom portion 26 is formed flat.

Further, as shown in FIGS. 1 (a) and 1 (b), the second flaps 9 and 10 are composed of a pair of first flaps 7,
The adhesive piece 1 is sandwiched between 8 and over a relatively large area.
Since the first and second flaps 1 and 12 are provided on the first flaps 7 and 8 formed to be larger than the second flaps 9 and 10 and can bond a relatively large area,
The adhesive strength with the flaps 9 and 10 is high, and the load resistance can be improved.

When the article is removed from the inside of the packaging box 1 and then folded again in a flat shape, first, the extending portion 1
The rocking portions 19b and 23b and the loose pieces 22, which are provided in the 9, 23,
24 and 24 are erected via the first escape crease lines 20 and 25, and the flaps 7, 8, 9, while maintaining the state for a while.
By tilting 10 inside the body 27, the flaps 7, 8, 9, 10 are housed inside the side plates 2, 3, 4, 5 and can be easily folded flat.

In the present embodiment, the extension portion 1
9, 23 and the swinging portions 19b, 23b, the loose pieces 2
2 and 24 are provided to increase the area covering the bottom 26,
If the second flaps 9 and 10 can be covered by the extending portions 19 and 23 and the swinging portions 19b and 23b, the loose pieces 22 and 24 need not be provided as shown in FIG. Also in this case, the respective extension parts 19, 23,
Since the swinging portions 19b and 23b form the inner surface side of the bottom portion 26 substantially flat and sandwich the second flaps 9 and 10 over a relatively wide area, the load bearing capability can be improved.

[0033]

As is apparent from the above, according to the present invention, the first flap is provided with the extending portion, so that the second flap is hidden and formed flat on the inner surface side of the bottom portion. can do.

Further, each first flap covers the bottom portion by the extending portion and the swinging portion and securely holds each second flap, and the adhesive piece is formed relatively large on each first flap. Therefore, not only the adhesive strength between the first flap and the second flap but also the load resistance can be improved.

Further, when each side plate is formed into a square tubular shape from a flat state, even if the swinging portions of the extending portions of the tilting first flaps come into contact with each other, both swinging movements are caused by the escape fold line. It is possible to smoothly form the bottom portion by swinging the portions in directions away from each other.

Further, by providing the free piece on each swinging portion, it is possible to cover the bottom portion over a wider range and more reliably sandwich the second flaps so that the inner surface side of the bottom portion is formed flat. When each side plate is formed into a rectangular tube shape from a flat state, even if the loose pieces come into contact with each other due to the tilting of the first flap, the other loose fold lines cause the loose pieces to move away from each other. The bottom can be smoothly formed by rocking.

Therefore, according to the present invention, it is possible to provide a bottom-lock type packaging box having a substantially flat bottom portion, high load resistance, and easy to assemble and fold.

[Brief description of drawings]

FIG. 1A is a plan view of the packaging box of the present embodiment with an upper portion cut off, and FIG. 1B is a bottom view of the packaging box of the present embodiment.

FIG. 2 is a development view of the packaging box shown in FIG.

FIG. 3 is an explanatory view showing a part of an assembling process of the packaging box shown in FIG.

FIG. 4 is an explanatory view showing a part of an assembling process of the packaging box shown in FIG.

FIG. 5 is a plan view showing a packaging box according to another embodiment of the present invention with an upper portion cut off.

FIG. 6A is a plan view of a conventional packaging box with an upper portion cut off, and FIG. 6B is a bottom view of the conventional packaging box.

7 is a development view of the packaging box shown in FIG.

FIG. 8A is a plan view of a conventional packaging box with an upper portion cut off, and FIG. 8B is a bottom view of the conventional packaging box.

9 is a development view of the packaging box shown in FIG.

10 is an explanatory view showing a part of an assembling process of the packaging box shown in FIG.

[Explanation of symbols]

1 ... Packaging box, 2, 3 ... 1st side plate, 4, 5 ... 2nd side plate,
7, 8 ... 1st flap, 9, 10 ... 2nd flap, 1
1, 12 ... Adhesive piece, 19, 23 ... Extension part, 19b, 23
b ... rocking part, 20, 25 ... first escape fold line 21,
26 ... 2nd escape fold line, 22, 24 ... free piece, 26
... bottom, 27 ... body.

Claims (2)

[Claims] 1. A pair of rectangular first side plates and a pair of rectangular second side plates.
Each of the side plates is alternately arranged in one direction via a fold line, is continuously provided to the lower end edge of each first side plate via a fold line, and is folded back to the inner surface side of each first side plate by the fold line. A pair of superposed first flaps and a pair of second flaps, which are continuously provided to the lower end edges of the respective second side plates via fold lines and are folded back to the inner surface side of the respective second side plates by the fold lines. And extending from the one end of the lower edge of the second side plate to the leading edge of the first flap at an angle of 45 ° with respect to the lower edge of the second side plate. And a first side plate located on one side is adjacent to the first side plate by a fold line. The adhesive piece is provided continuously through the fold line and is folded and polymerized on the outer surface side of the first flap by the fold line. The adhesive piece is folded back to the inner surface of the second side plate and polymerized, and the adhesive piece is attached to the outer surface of the second flap. The second side plate located on the other side is bonded to the inner surface side of the first side plate adjacent to the second side plate by the crease line and polymerized, and the adhesive piece is bonded to the outer surface side of the second flap. Glue through the first, each first
When the side plate and each of the second side plates are spread through each fold line so as to be positioned at right angles to each other to form a rectangular tubular body, each second flap and each first flap are connected by each adhesive piece. In a packaging box in which a closed bottom portion is formed at a right angle to each first side plate and each second side plate in a closed state, the first flap faces the second flap connected by the adhesive piece. And an extension portion having a tip edge that overlaps the inner surface of the other second flap and that abuts a lower edge of another first side plate facing the first side plate in which the first flap is continuously provided; A bottom-lock type packaging box, comprising: a swinging portion that is swingable via a relief fold line extending from the leading edge of the projecting portion toward the center of the first flap. 2. The bottom lock according to claim 1, wherein a swingable swingable piece is continuously provided on an inner side edge of the swingable portion through another escape fold line. Style packaging box.