Packing box

Abstract

To provide a packaging box in which a locking piece can be easily inserted into a locking hole.SOLUTION: A packaging box 1 includes a lid wall 15 that is connected to the upper end of a first side wall 10 on one side and closes the opening of a peripheral wall T, a lid insertion piece that is connected to the tip of the lid wall 15 via a bending structure 33 and inserted into the inside of the peripheral wall T, a locking hole 30 formed near the boundary line between the lid wall 15 and the lid insertion piece, and a locking piece 18 that is connected to the first side wall 10 on the other side and inserted into the locking hole 30. The bending structure 33 has a pair of insertion fold lines L6 formed on the same straight line as the boundary line, and a pair of V-shaped fold lines L7 that are formed by bifurcating from both inner ends of the pair of insertion fold lines L6 to form a V-shape between both inner ends of the pair of insertion fold lines L6 and both side edges of the locking hole 30. Both sides of the locking piece 18 inserted into the locking hole 30 slide into a pair of inclined surface parts 34 formed in a region defined by both side edges of the locking hole 30 and the pair of V-shaped fold lines L7.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a packing box.

Background Art

[0002] Patent Document 1 discloses a security sealed box in which a lid engaging piece connected to the tip of an opening / closing lid plate is inserted along the inside of a front wall, and a locking piece extending from the tip side of a hinge piece provided on the front wall is inserted into a slit-shaped locking hole provided at the base of the lid engaging piece for sealing. The locking piece is configured to be press-fitted into the locking hole and prevented from coming out of the locking hole.

Prior Art Documents

Patent Documents

[0003] [[ID=二十一]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described security sealed box, since the locking hole is a narrow slit shape, it is difficult to insert the locking piece into the locking hole. Further, since the locking piece is press-fitted while interfering with both edge portions of the locking hole on both sides, there is also a risk that both side portions of the locking piece are crushed or the edge portions of the locking hole are torn.

[0005] The present invention provides a packing box that can easily insert a locking piece into a locking hole in consideration of the above circumstances.

Means for Solving the Problems

[0006] The packing box alternately includes a pair of first side walls and a pair of second side walls arrangementThe lid comprises a circumferential wall formed in a cylindrical shape, a lid wall connected to the upper end of either of the pair of first side walls and closing the opening of the circumferential wall, a lid insertion piece connected to the tip of the lid wall via a bending structure and inserted into the inside of the circumferential wall and facing the back surface of the other of the pair of first side walls, a locking hole formed near the boundary line between the lid wall and the lid insertion piece, and a locking piece connected to the other of the pair of first side walls and inserted into the locking hole with its tip facing along the back surface of the lid wall, wherein the bending structure is the lid wall or the lid insertion The piece has a pair of insertion fold lines formed on the same line as the boundary line from both ends of the piece to the vicinity of the locking hole, and a pair of V-shaped fold lines that branch out from both inner ends of the pair of insertion fold lines and are formed in a V-shape from both inner ends of the pair of insertion fold lines to both side edges of the locking hole, and a pair of inclined surfaces are formed in the region demarcated by both side edges of the locking hole and the pair of V-shaped fold lines, which are inclined relative to the lid wall and the lid insertion piece, and both sides of the locking piece inserted into the locking hole slide against the pair of inclined surfaces.

[0007] In this case, the locking hole has an opening body formed along the boundary line and a pair of side openings extending diagonally from both ends of the opening body toward the side of the lid wall toward each other, and the V-shaped fold line has a first inclined fold line formed between the inner end of the insertion fold line and the inflection point between the opening body and the side opening, and a second inclined fold line formed between the inner end of the insertion fold line and the vicinity of the end of the side opening, and the inclined surface is preferably demarcated by the edge of the side opening and the pair of V-shaped fold lines.

[0008] In this case, the locking piece is formed between a pair of notches cut into the upper side of one of the pair of first side walls and has a hinge portion connected to the other first side wall via a first locking fold line, and a locking body portion connected to the tip of the hinge portion via a second locking fold line and inserted into the locking hole, wherein a pair of notches are recessed on the base end side of the locking body portion so as to approach each other from both ends, and when the locking body portion is inserted into the locking hole, the pair of inclined surfaces fit into the pair of notches.

[0009] In this case, the second locking fold line may be bent or curved so as to protrude from both ends of the locking body toward the center in the lateral direction toward the hinge portion, and the locking body may have a bend line formed so as to divide it in half horizontally.

[0010] In this case, the opening body may have a crescent shape with a lower edge that curves downward from the pair of side openings toward the center in the lateral direction.

[0011] In this case, the opening width of the opening body portion may be set to be slightly narrower than or equal to the distance between the pair of notches of the locking body portion, the opening width of the side opening may be set to be slightly wider than the depth of the notches of the locking body portion, and the overall opening width of the locking hole may be slightly wider than or equal to the overall width of the locking body portion. [Effects of the Invention]

[0012] According to the present invention, the locking piece can be easily inserted into the locking hole. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view showing a packaging box relating to one embodiment of the present invention. [Figure 2] This is a plan view showing a blank packaging box according to one embodiment of the present invention. [Figure 3A] This is a plan view showing an enlarged view of the area around the locking hole in a blank packaging box according to one embodiment of the present invention. [Figure 3B] This is a plan view showing an enlarged view of the area around the locking piece, of a blank packaging box according to one embodiment of the present invention. [Figure 4] This is a perspective view showing the state in which the peripheral wall of a packaging box according to one embodiment of the present invention has been formed. [Figure 5] This is a perspective view of a packaging box according to one embodiment of the present invention, showing the inner flap in a folded state. [Figure 6] A perspective view showing a state where an opening in a peripheral wall is closed, which is a packaging box according to an embodiment of the present invention. [Figure 7] A perspective view showing a process of inserting a locking piece into a locking hole, which is a packaging box according to an embodiment of the present invention. [Figure 8] A perspective view showing an enlarged process of inserting a locking piece into a locking hole, which is a packaging box according to an embodiment of the present invention. [Figure 9] A perspective view showing a state where an opening piece is opened, which is a packaging box according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0014] [[ID=1十七]] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that Fr, Rr, L, R, U, and D shown in the drawings indicate front, rear, left, right, top, and bottom. The front-rear direction, left-right direction, and up-down direction are orthogonal to each other. In this specification, terms indicating directions and positions are used for convenience of explanation and do not limit the technical scope of the present invention. Also, the terms indicating directions and positions are, in principle, based on the directions and positions when using the packaging box.

[0015] Referring to FIGS. 1 to 3, the packaging box 1 according to the embodiment will be described. FIG. 1 is a perspective view showing the packaging box 1. FIG. 2 is a plan view showing the blank 1A of the packaging box 1. FIGS. 3A and 3B are plan views showing an enlarged part of the blank 1A.

[0016] [[ID=2十五]] As shown in FIG. 1, the packaging box 1 is formed in a substantially rectangular parallelepiped shape by closing the upper and lower end surfaces of the peripheral wall T. The peripheral wall T is formed in a substantially square tube shape by alternately arranging a pair of first side walls 10 and a pair of second side walls 11 in the circumferential direction.

[0017] The packaging box 1 is assembled from the blank 1A shown in FIG. 2. The blank 1A is formed by punching out a single paper corrugated sheet using a die or the like. The corrugated sheet is, for example, a double-sided corrugated sheet in which a corrugated medium 9A is bonded to a face liner 9B and a back liner 9C (see also FIGS. 4 and 5). Note that FIGS. 2, 3A, and 3B show the face liner 9B side. In this specification, the direction parallel to the medium 9A of the corrugated sheet is referred to as the "corrugation direction", and the direction orthogonal to the corrugation direction is referred to as the "flow direction". "X" shown in the drawings indicates the "corrugation direction", and "Y" indicates the "flow direction".

[0018] [Blank] As shown in FIG. 2, the blank 1A includes a pair of first side walls 10, a pair of second side walls 11, a pair of first bottom walls 12, a pair of second bottom walls 13, a pair of inner flaps 14, a lid wall 15, a lid insertion piece 16, a folded-back wall 17, and a locking piece 18. Since the pair of first side walls 10 are generally of the same shape, in this specification, mainly, one first side wall 10 will be described. For the same reason, for the pair of second side walls 11, the pair of first bottom walls 12, the pair of second bottom walls 13, and the pair of inner flaps 14, mainly, one part will be described.

[0019] <First side wall, second side wall> The pair of first side walls 10 and the pair of second side walls 11 are alternately connected in the flow direction via a first folding line L1. The first side wall 10 and the second side wall 11 are formed in a substantially rectangular shape. Specifically, the first side wall 10 is formed in a substantially rectangular shape that is longer in the flow direction than the second side wall 11. A continuation piece 19 is connected to the free end of the first side wall 10 in the flow direction via the first folding line L1.

[0020] <First bottom wall> The first bottom wall 12 is connected to one end (lower end) of the first side wall 10 in the step direction via a second bend curve L2. The first bottom wall 12 is formed in a generally rectangular shape, and the dimension of the first bottom wall 12 in the step direction (extension dimension) is set to be slightly longer than half the dimension of the first side wall 10 in the flow direction. A roughly triangular interlocking recess 20 is cut out at the tip side of the first bottom wall 12. A bottom fold line L4 is formed diagonally on the first bottom wall 12 from the interlocking recess 20 toward the lower corner of the second side wall 11, and the bottom adhesive portion 21 is defined by the bottom fold line L4. In addition, a bottom auxiliary fold line L5 is formed diagonally on the first bottom wall 12 from the abutment of the interlocking recess 20 toward the free end of the first bottom wall 12, so as to be symmetrical with the inclined edge of the interlocking recess 20, and the bottom auxiliary piece 22 is defined by the bottom auxiliary fold line L5.

[0021] <Second bottom wall> The second bottom wall 13 is connected to one end (lower end) of the second side wall 11 in the step direction via a second bent curve L2. The second bottom wall 13 is formed in a roughly trapezoidal shape, gradually narrowing from the base to the tip. The step direction dimension (extension dimension) of the second bottom wall 13 is set to approximately half the flow direction dimension of the first side wall 10.

[0022] <Inner flap> The inner flap 14 is connected to the other end (upper end) of the second side wall 11 in the step direction via a third bend curve L3. The inner flap 14 is formed in a generally rectangular shape, and the step-direction dimension (extension dimension) of the inner flap 14 is set to approximately half the extension dimension of the second bottom wall 13.

[0023] The first to third fold lines L1 to L3 and the bottom auxiliary fold line L5 are general-purpose creases that indent the corrugated cardboard sheet from the back liner 9C. The bottom fold line L4 is a reverse crease that indents the corrugated cardboard sheet from the front liner 9B. The general-purpose creases have the function of folding the corrugated cardboard sheet so that the back liner 9C faces inward (forward fold), and the reverse crease has the function of folding the corrugated cardboard sheet so that the front liner 9B faces inward (reverse fold). Note that these first to third fold lines L1 to L3, etc., are not limited to general-purpose creases or reverse creases; any line that allows the corrugated cardboard sheet to be folded in the desired direction, such as perforations, may be used.

[0024] <Lid wall> The cover wall 15 is connected to the other end (upper end) in the step direction of one side wall 10 (the side of the connecting piece 19) via a third bend curve L3. The cover wall 15 is formed in a generally rectangular shape, and the dimension of the cover wall 15 in the step direction (extension dimension) is approximately the same as the dimension of the second side wall 11 in the flow direction. As will be described in detail later, the cover wall 15 closes the opening TA above the peripheral wall T. On both sides of the tip of the cover wall 15 in the flow direction, a pair of finger rests 23 are recessed in a roughly semicircular shape.

[0025] <Lid insertion piece> The lid insertion piece 16 is connected to the stepped end (free end) of the lid wall 15 via a bent structure 33. The lid insertion piece 16 is formed in a generally rectangular shape, and the stepped dimension (extension dimension) of the lid insertion piece 16 is set to be sufficiently shorter (lower) than the stepped dimension (height) of the first side wall 10.

[0026] (Locking hole) A locking hole 30 is formed near the boundary line between the lid wall 15 and the lid insertion piece 16 by cutting along a single cutting line. The locking hole 30 (cutting line) is formed in a roughly U-shape that is convex from the lid wall 15 toward the lid insertion piece 16 in the central region in the flow direction of the lid insertion piece 16, etc. As shown in Figure 3A, the locking hole 30 has an opening body portion 31 and a pair of side openings 32. Since the pair of side openings 32 are symmetrical in shape with respect to the opening body portion 31, this specification will mainly describe one of the side openings 32.

[0027] (Opening body section) The opening body portion 31 is formed on the lid insertion piece 16 along the boundary line between the lid wall 15 and the lid insertion piece 16. More specifically, the opening body portion 31 is formed by cutting a slightly curved cutting line on the base end side in the stepped direction of the lid insertion piece 16 so as to bulge outwards towards the free end side.

[0028] (Side opening) The pair of side openings 32 extend diagonally from both ends of the opening body 31 in the flow direction toward the lid wall 15, moving away from each other. More specifically, the side openings 32 are bent relative to the opening body 31 and formed by cutting a straight line from the lid insertion piece 16 across the boundary line with the lid wall 15 toward the lid wall 15. The side openings 32 are formed in the lid insertion piece 16 near the inflection point P1 with respect to the opening body 31, and the majority of the side openings 32, excluding the area near the inflection point P1, are formed in the lid wall 15. The end portion of the side openings 32 bends relative to the rest of the opening (inflection point P2) and extends slightly toward the base end of the lid wall 15.

[0029] (Kaikō Line) A pair of opening lines 24 are formed on the lid wall 15 at the base end in the step direction of the pair of side openings 32 (the cutting lines that make up the pair). The pair of opening lines 24 are inclined to move away from each other from the tip side to the base end in the step direction of the lid wall 15. Each opening line 24 is a so-called zipper with multiple roughly L-shaped cuts arranged side by side. In detail, each opening line 24 is composed of one full cut 25 and one half cut 26 arranged in the step direction with spacing between them, starting from the side of the side opening 32. In addition, an auxiliary cut line 27 is formed on the lid wall 15 on a hypothetical straight line connecting the ends of the pair of half cuts 26. The full cut 25 is a cut that penetrates the lid wall 15 in the thickness direction, while the half cut 26 and auxiliary cut line 27 are cuts (half cut lines) that cut the lid wall 15 from the back liner 9C by about half its thickness. The area enclosed by the locking hole 30 (and the cutting lines that constitute it), the pair of opening lines 24, and the auxiliary cutting line 27 (or a hypothetical straight line) constitutes the opening piece 28 that is cut from the lid wall 15 when the packaging box 1 is opened (details will be described later). Each opening line 24 may be formed by only a plurality of full cuts 25 or only a plurality of half cuts 26, and may be not limited to a zipper, but may be, for example, a perforation. In addition, each opening line 24 and auxiliary cutting line 27 may be omitted if they are not needed (not shown).

[0030] (bending structure) As shown in Figures 2 and 3A, the bent structure 33 has a pair of insertion fold lines L6 and a pair of V-shaped fold lines L7. The pair of insertion fold lines L6 are formed on the same straight line as the boundary line between the lid wall 15 and the lid insertion piece 16, from both ends (both sides) in the flow direction of the lid wall 15 or lid insertion piece 16 to the vicinity of the locking hole 30. In other words, the pair of insertion fold lines L6 constitute a part of the boundary line between the lid wall 15 and the lid insertion piece 16. The pair of V-shaped fold lines L7 are formed in a V-shape by branching from both inner ends of the pair of insertion fold lines L6 to both side edges of the locking hole 30. Since the pair of insertion fold lines L6 and the pair of V-shaped fold lines L7 are symmetrical with respect to the locking hole 30, this specification will mainly describe one insertion fold line L6 and one V-shaped fold line L7. Furthermore, while the insertion fold line L6 and the V-shaped fold line L7 are general-purpose creases, they are not limited to these; any line that allows the corrugated cardboard sheet to be folded in the desired direction, such as perforations, may be used.

[0031] As shown in Figure 3A, the V-shaped fold line L7 has a first inclined fold line L7A and a second inclined fold line L7B. The first inclined fold line L7A is formed in a straight line connecting the inner end of the insertion fold line L6 and the inflection point P1 between the opening body 31 and the side opening 32. The second inclined fold line L7B is formed in a straight line connecting the inner end of the insertion fold line L6 and the bend (inflection point P2) near the end of the side opening 32. The first inclined fold line L7A and the second inclined fold line L7B are inclined to move away from each other from the insertion fold line L6 toward the locking hole 30. The first inclined fold line L7A is formed on the lid insertion piece 16, and the second inclined fold line L7B is formed on the lid wall 15. The second inclined fold line L7B is formed to be shorter than the first inclined fold line L7A, and the angle between the imaginary line extending the insertion fold line L6 toward the locking hole 30 and the second inclined fold line L7B is set to be larger than the angle between the imaginary line and the first inclined fold line L7A. ​​In other words, the inclination angle of the second inclined fold line L7B is larger than the inclination angle of the first inclined fold line L7A. ​​In this embodiment, the second inclined fold line L7B is a general-purpose crease line, but to make it easier to fold, it is preferable to make it a half-cut line by cutting about half the thickness of the corrugated cardboard sheet from the back liner 9C (not shown).

[0032] (Sloped surface part) A pair of inclined surfaces 34 are formed in the region demarcated by the edges of the pair of side openings 32 (both side edges of the locking holes 30) and the pair of V-shaped fold lines L7. Each inclined surface 34 is defined by the side openings 32 (the cutting lines that form them), the first inclined fold line L7A, and the second inclined fold line L7B, and is formed in a substantially triangular shape.

[0033] <Folding wall> Next, as shown in Figure 2, the folded wall 17 is connected to the other end (upper end) of the first side wall 10 in the step direction via a third bend curve L3. The folded wall 17 is formed in a generally rectangular shape, and the step-direction dimension (extension dimension) of the folded wall 17 is approximately the same as the extension dimension of the inner flap 14.

[0034] <Locking piece> The locking piece 18 is formed to divide the third bend curve L3 into two, extending from the upper part of the other first side wall 10 to the lower part of the bend wall 17. As shown in Figure 3B, the locking piece 18 has a hinge portion 40 and a locking body portion 41.

[0035] The hinge portion 40 is formed between a pair of notches 42 cut into the upper side of the other first side wall 10 and is connected to the other first side wall 10 via a first locking fold line L8. The pair of notches 42 are inclined to approach each other downward from the upper end (third fold curve L3) of the other first side wall 10. The hinge portion 40 is formed in a substantially trapezoidal shape that narrows downward. The locking body portion 41 is defined by a notch 43 cut into the lower side of the folded wall 17 and is connected to the tip (upper end) of the hinge portion 40 via a second locking fold line L9. The notch 43 is formed in a substantially U-shape so as to protrude upward from the lower end (third fold curve L3) of the folded wall 17. The locking body portion 41 is formed in a substantially rectangular shape with the corners on the tip side beveled. Note that the first locking fold line L8 is a reverse crease line, and the second locking fold line L9 is a general-purpose crease line, but it is not limited to these; any line that allows the corrugated cardboard sheet to be folded in the desired direction, such as perforations, is acceptable.

[0036] (Second locking fold line) The second locking fold line L9 is bent so as to protrude from both ends of the locking body portion 41 toward the center in the flow direction (lateral direction) toward the hinge portion 40. In other words, the second locking fold line L9 is formed in a substantially V shape. In this embodiment, for example, the difference in height between the ends of the second locking fold line L9 in the flow direction and the center is about 1 mm. The second locking fold line L9 may also be curved so as to protrude from both ends of the locking body portion 41 toward the center in the lateral direction toward the hinge portion 40, and may be formed in a substantially U shape (not shown).

[0037] (Bent line) Furthermore, a bend line L10 is formed on the locking body portion 41 so as to divide it in the flow direction (lateral direction). The bend line L10 is a half-cut line formed in a straight line in the step direction from the V-shaped bend of the second locking fold line L9 to the tip of the locking body portion 41. Note that although the bend line L10 is a half-cut line, it is not limited to these, and any line that can be used to fold the corrugated cardboard sheet in the desired direction may be used, such as a reverse crease line or a perforation line.

[0038] (Notched section) Furthermore, a pair of notches 44 are recessed into the base end of the locking body portion 41, with both ends approaching each other. Each notch 44 is formed by recessing the cut line 43 in a roughly V-shape (roughly triangular shape). Due to the recessing of the pair of notches 44, the free end side of the locking body portion 41 is relatively wider than the base end side in the step direction.

[0039] As shown in FIGS. 3A and 3B, the opening width W2 of the opening main body 31 is set to be slightly narrower than the distance W5 between the pair of notch portions 44 of the locking main body 41 (W2 < W5). The opening width W3 of the side opening 32 is set to be slightly wider than the depth W6 of the notch portion 44 of the locking main body 41 (W3 > W6). And the overall opening width W1 of the locking hole 30 is set to be slightly wider than the overall lateral width W4 of the locking main body 41 (W1 > W4). Note that the dimensions of the above-described respective portions are examples, and the opening width W2 of the opening main body 31 may be set to be the same as the distance W5 between the pair of notch portions 44 of the locking main body 41 (W2 ≦ W5). The overall opening width W1 of the locking hole 30 may be set to be the same as the overall lateral width W4 of the locking main body 41 (W1 ≧ W4).

[0040] [Assembly of Packaging Box] Next, referring to FIGS. 1, 4 to 8, the assembly procedure (sealing procedure) of the packaging box 1 will be described. FIG. 4 is a perspective view showing a state in which the peripheral wall T of the packaging box 1 is formed. FIG. 5 is a perspective view showing a state in which the inner flap 14 is bent. FIG. 6 is a perspective view showing a state in which the opening TA of the peripheral wall T is closed. FIG. 7 is a perspective view showing a process of inserting the locking piece 18 into the locking hole 30. FIG. 8 is an enlarged perspective view showing a process of inserting the locking piece 18 into the locking hole 3.The case where an operator assembles the packaging box 1 will be described here as an example.

[0041] Although illustration is omitted, as an initial state before assembly, the packaging box 1 is double-folded. Specifically, first, the first bottom wall 12 and the second bottom wall 13 are folded inward along the second folding line L2, and the bottom adhesion portion 21 of the first bottom wall 12 is reversely folded along the bottom folding line L4. The first side wall 10 and the second side wall 11 located on both outer sides in the flow direction of the blank 1A are folded along the first folding line L1, the substitute piece 19 is adhered to the back surface (back liner 9C) of the second side wall 11 on the opposite side, and the bottom adhesion portion 21 is adhered to the front surface (front liner 9B) of the second bottom wall 13.

[0042] The worker folds a pair of first side walls 10 and a pair of second side walls 11 of the folded packaging box 1 along a first fold line L1 so that they are approximately perpendicular to each other (forward folding). The pair of first side walls 10 and the pair of second side walls 11 are arranged alternately in the circumferential direction, forming a rectangular tubular circumferential wall T with an opening TA at the upper end (see Figure 4). As the circumferential wall T is formed, the first bottom wall 12 and the second bottom wall 13, which are folded inward, are pushed downward while stretching the reverse-folded bottom adhesive portion 21 (not shown). In the process of the pair of first bottom walls 12 being pushed out, the pair of bottom auxiliary pieces 22 interfere with each other and are folded in the forward direction along the bottom auxiliary fold line L5, and the pair of interlocking recesses 20 interlock (not shown). When the pair of interlocking recesses 20 interlock, each bottom auxiliary piece 22 is stretched (returns to its original shape) by the restoring force around the bottom auxiliary fold line L5. As a result, the lower end of the peripheral wall T is closed by a pair of first bottom walls 12 and a pair of second bottom walls 13, forming the bottom surface of the packaging box 1 (not shown). In other words, the bottom surface of the packaging box 1 is a so-called one-touch bottom that is automatically formed when the peripheral wall T is formed.

[0043] Next, as shown in Figure 4, the worker folds the folded wall 17 inward along the third fold line L3 towards the perimeter wall T. The folded wall 17 is folded approximately 180 degrees, with both left and right ends in contact with the back surfaces of the pair of second side walls 11, and overlaps with the back surface of the front first side wall 10. Because both left and right ends of the folded wall 17 are in contact with the pair of second side walls 11, upward movement due to restoring force around the fold is suppressed. As the folded wall 17 is folded, the locking body portion 41 of the locking piece 18 is cut out from the folded wall 17 along the cut line 43 and protrudes upward from the upper end of the front first side wall 10.

[0044] Next, the worker places the product (not shown) inside the peripheral wall T, and then folds the pair of inner flaps 14 inward along the third fold line L3 (see Figure 5). The worker then bends the locking piece 18 (hinge portion 40) forward along the first locking fold line L8 (reverse fold) (see Figure 5), folds the lid insertion piece 16 at approximately a right angle using the folding structure 33 (forward fold), and inserts the lid insertion piece 16 into the inside of the peripheral wall T while bending the lid wall 15 forward along the third fold line L3 (see Figure 6). The lid insertion piece 16 is inserted into the inside of the peripheral wall T while in contact with the folded wall 17 (surface), and in an approximately vertical position, it faces the back surface of the first side wall 10 in front of the folded wall 17. The lid wall 15 is in an approximately horizontal position, closing the opening TA of the peripheral wall T (see Figure 6).

[0045] As shown in Figure 6, the opening body portion 31 is formed by a curved cutting line that protrudes on the free end side of the lid insertion piece 16. Therefore, when the lid insertion piece 16 is folded by the folding structure 33, the opening body portion 31 opens in a crescent shape with a lower edge 31A that curves downward from the pair of side openings 32 toward the center in the left-right direction (lateral direction). In reality, the opening body portion 31 is a slit-shaped opening that is slightly wider than the thickness of the corrugated cardboard sheet (locking piece 18). Also, when the lid insertion piece 16 is folded by the folding structure 33, the tip (front end) of the opening piece 28 protrudes slightly forward relative to the lid insertion piece 16. The lid insertion piece 16 bends along the V-shaped fold line L7 (first inclined fold line L7A, second inclined fold line L7B) near the locking hole 30, so that the pair of inclined surfaces 34 demarcated by the pair of V-shaped fold lines L7 etc. are inclined relative to the lid wall 15 and the lid insertion piece 16 (see also Figure 8). Each inclined surface 34 slopes downward from rear to front (from the lid wall 15 side to the lid insertion piece 16 side). As the pair of inclined surfaces 34 are inclined, a pair of side openings 32 are slightly opened, continuous with the crescent-shaped opening body 31.

[0046] Next, as shown in Figures 7 and 8, the worker folds the locking body portion 41 of the locking piece 18 in the right direction along the second locking fold line L9, and inserts the tip of the locking body portion 41 into the locking hole 30 while raising the hinge portion 40 that was bent (reverse-folded) along the first locking fold line L8. Because the second locking fold line L9 is bent in a roughly V-shape, when the locking body portion 41 is folded in the right direction along the second locking fold line L9, it is reverse-folded along the bending line L10 so that both sides in the left-right direction are flipped up. The locking body portion 41 is reverse-folded along the bending line L10 to become roughly V-shaped to match the curved lower edge 31A of the opening body portion 31, and is inserted into the opening body portion 31. As the locking body portion 41 is inserted into the opening body portion 31, both left and right sides of the locking body portion 41 come into contact with the pair of inclined surfaces 34, which are in an inclined position, and slide along the surface of the pair of inclined surfaces 34 as it is inserted into the pair of side openings 32. The locking body portion 41, which is bent in the reverse direction along the bending line L10, is easy to insert into the crescent-shaped opening body portion 31 and makes it easy to bring the flipped-up left and right sides into contact with the pair of inclined surfaces 34. The locking body portion 41 is inserted into the locking hole 30 while in a position that follows the back surface of the lid wall 15, and the hinge portion 40 is returned to a position that is substantially flush with the front first side wall 10 (see Figure 1).

[0047] With the locking body portion 41 inserted into the locking hole 30, the pair of inclined surfaces 34 fit into the pair of notches 44 of the locking body portion 41 (see Figure 1). In other words, the base end surface (cross-section) of the locking body portion 41 exposed by the pair of notches 44 interferes with (engages with) the back surface of the pair of inclined surfaces 34.

[0048] With the above steps completed, packaging box 1 is assembled and sealed (see Figure 1).

[0049] Next, with reference to Figure 9, we will briefly explain how to open the sealed packaging box 1. Figure 9 is a perspective view showing the opening tab 28 in the opened state.

[0050] The user places their fingers on the tip of the opening piece 28 that protrudes slightly forward (see Figure 1) and pulls up the opening piece 28. The opening piece 28 is cut along a pair of opening lines 24 (full cut 25, half cut 26) and opens upward along the auxiliary cut line 27 (folded in the reverse direction) (see Figure 9). As a result the locking body 41 is exposed, the user detaches the locking body 41 from the inside of the peripheral wall T (see Figure 9) and opens the lid wall 15 while pulling the lid insertion piece 16 out of the peripheral wall T (not shown). This opens the opening TA, and the product contained in the packaging box 1 can be removed.

[0051] As described above, in the packaging box 1 according to this embodiment, a pair of inclined surfaces 34 are formed adjacent to both side edges of the locking hole 30, and both sides of the locking piece 18 inserted into the locking hole 30 slide against the pair of inclined surfaces 34 (see Figures 7 and 8). With this configuration, the locking piece 18 can be inserted into the locking hole 30 while guiding both sides of the locking piece 18 along the pair of inclined surfaces 34. As a result, even if the locking hole 30 is slit-shaped, the locking piece 18 can be easily inserted into the locking hole 30. Furthermore, the sliding of both the left and right sides of the locking piece 18 along the pair of inclined surfaces 34 guides the locking piece 18 to the precise position where it can be inserted into the locking hole 30. As a result, the left and right sides of the locking piece 18 do not interfere excessively with the edge of the locking hole 30, thereby suppressing crushing of both sides of the locking piece 18 and tearing of the edge of the locking hole 30.

[0052] Furthermore, in the packaging box 1 according to this embodiment, a pair of notches 44 are recessed on the base end side of the locking body portion 41, and the inclined surface portion 34 fits into the notches 44 when the locking body portion 41 is inserted into the locking hole 30 (see Figure 1). With this configuration, if someone tries to pull out the locking body portion 41 that has been inserted into the locking hole 30, the base end surface of the locking body portion 41 exposed in the notches 44 interferes with the back surface of the inclined surface portion 34, thereby restricting the removal of the locking body portion 41. As a result, the pair of inclined surface portions 34 ensure ease of insertion of the locking body portion 41 into the locking hole 30, while making it difficult to pull out the locking body portion 41 from the locking hole 30. Consequently, the packaging box 1 cannot be opened unless the opening piece 28 is broken at the opening line 24 or the locking body portion 41 is torn off from the hinge portion 40, thus preventing unauthorized opening of the packaging box 1.

[0053] Furthermore, in the packaging box 1 according to this embodiment, since the second locking fold line L9 is bent, when the locking body portion 41 is folded along the second locking fold line L9, both the left and right sides are reverse-folded along the fold line L10 so as to flip up (see Figures 7 and 8). With this configuration, by reverse-folding the locking body portion 41 along the fold line L10 to form a roughly V-shape, both sides of the locking body portion 41 can be easily aligned with the pair of inclined surfaces 34. As a result, both sides of the locking body portion 41 can be properly guided to the side opening 32, and the locking body portion 41 can be easily inserted into the locking hole 30.

[0054] Furthermore, according to the packaging box 1 of this embodiment, since the opening body portion 31 is formed in a crescent shape with a curved lower edge 31A, the locking body portion 41, which is folded in the opposite direction along the bending line L10 to form a roughly V-shape, can be properly inserted into the opening body portion 31 (see Figures 6 to 8).

[0055] Furthermore, according to the packaging box 1 of this embodiment, by setting the various opening widths W1 to W3 of the locking hole 30 and the various dimensions of the locking piece 18 (width W4, spacing W5, depth W6) as already described (see Figures 3A and 3B), it becomes possible to make it easy to insert the locking body 41 into the locking hole 30 and difficult to remove.

[0056] In the packaging box 1 according to this embodiment, the first inclined fold line L7A was formed to connect the inner end of the insertion fold line L6 and the inflection point P1 (see Figure 3A), but the present invention is not limited thereto. The first inclined fold line L7A only needs to be formed between the inner end of the insertion fold line L6 and the inflection point P1 between the opening body 31 and the side opening 32. For example, both ends of the first inclined fold line L7A may be separated from at least one of the inner end of the insertion fold line L6 and the inflection point P1 (they may not be in contact). Also, the second inclined fold line L7B was formed to connect the inner end of the insertion fold line L6 and the vicinity of the end of the side opening 32 (inflection point P2) (see Figure 3A), but the present invention is not limited thereto. The second inclined fold line L7B only needs to be formed between the inner end of the insertion fold line L6 and the vicinity of the end of the side opening 32. For example, both ends of the second inclined fold line L7B may be separated from at least one of the inner end of the insertion fold line L6 and the vicinity of the end of the side opening 32 (they do not need to be in contact).

[0057] Furthermore, in the packaging box 1 according to this embodiment, a folded wall 17 was attached to the upper end of the other first side wall 10, but this is not limited to this, and the folded wall 17 may be omitted (not shown).

[0058] Furthermore, in the packaging box 1 according to this embodiment, a pair of notches 44 were recessed in the locking body portion 41 of the locking piece 18. However, if, for example, it is desired that the locking piece 18 be removable from the locking hole 30, the pair of notches 44 may be omitted, and the overall opening width W1 of the locking hole 30 and the overall width W4 of the locking body portion 41 may be adjusted as appropriate (not shown).

[0059] Furthermore, in the packaging box 1 according to this embodiment, the second locking fold line L9 was bent (or curved), but it is not limited to this, and the second locking fold line L9 may be formed in a straight line in the flow direction (lateral direction) without being bent or curved (not shown). Also, although a bend line L10 was formed on the locking body portion 41, the bend line L10 may be omitted regardless of whether the second locking fold line L9 is bent (curved) or in a straight line (not shown).

[0060] Furthermore, in the packaging box 1 according to this embodiment, the opening body portion 31 was formed in a crescent shape with a curved lower edge 31A, but it is not limited to this, and the opening body portion 31 may be, for example, a straight slit, or a single cut whether curved or straight (not shown).

[0061] Furthermore, although the packaging box 1 according to this embodiment was formed from a double-sided corrugated cardboard sheet made of paper, it is not limited to this and may be formed from a single-sided corrugated cardboard sheet, a double-sided corrugated cardboard sheet, or cardboard, or a resin board (sheet), etc.

[0062] The above description of embodiments illustrates one aspect of the packaging box according to the present invention, and the technical scope of the present invention is not limited to the above embodiments. The present invention may be modified, substituted, or transformed in various ways without departing from the spirit of the technical idea, and the claims include all embodiments that may fall within the scope of the technical idea. [Explanation of Symbols]

[0063] 1 packaging box 10 First side wall 11. Second side wall 15 Lid wall 16 Lid insertion piece 18 Locking piece 30 locking holes 31 Opening body 31A Lower edge 32 Side opening 33 Bending structure 34 Slope section 40 Hinge section 41 Locking body 42 Cutting line 44 Notch L6 Insertion Fold Line L7 V-shaped fold line L7A 1st inclined fold line L7B 2nd inclined fold line L8 1st locking fold line L9 2nd locking fold line L10 bending line P1 inflection point T Peripheral wall TA opening W1 Overall opening width of the locking hole W2 Opening width of the opening body W3 side opening width W4 Overall width of the locking body W5 The distance between the pair of notches. W6 Depth of the notch

Claims

1. A peripheral wall (T) is formed in a cylindrical shape by alternately connecting a pair of first side walls (10) and a pair of second side walls (11), A cover wall (15) is provided in connection with the upper end of either of the pair of first side walls and closes the opening (TA) of the peripheral wall, A lid insertion piece (16) is connected to the tip of the lid wall via a bent structure (33), inserted into the inside of the peripheral wall and facing the back surface of the other of the pair of first side walls, A locking hole (30) is formed to divide the bent structure between the lid wall and the lid insertion piece in the direction in which the bent structure extends, The device comprises a locking piece (18) which is connected to the other of the pair of first side walls and is inserted into the locking hole with its tip facing along the back surface of the lid wall, The aforementioned bent structure is A pair of insertion fold lines (L6) are formed to demarcate the lid wall and the lid insertion piece from both ends of the lid wall or the lid insertion piece to the vicinity of the locking hole, Between the inner ends of the pair of insertion fold lines and the side edges of the locking hole, a pair of V-shaped fold lines (L7) are formed by branching from the inner ends of the pair of insertion fold lines in a V-shape, In the region demarcated by both side edges of the locking hole and the pair of V-shaped fold lines, a pair of inclined surfaces (34) are formed that are inclined relative to the lid wall and the lid insertion piece. A packaging box characterized in that both sides of the locking piece, which is inserted into the locking hole, slide against the pair of inclined surfaces.

2. The aforementioned locking hole is, The opening body portion (31) extends along the direction in which the aforementioned insertion fold line extends, It has a pair of side openings (32) that extend diagonally from both ends of the opening body toward the side of the lid wall so as to be separated from each other, The aforementioned V-shaped fold line is, A first inclined fold line (L7A) is formed between the inner end of the aforementioned insertion fold line and the inflection point (P1) between the opening body and the side opening, It has a second inclined fold line (L7B) formed between the inner end of the aforementioned insertion fold line and the vicinity of the end of the side opening, The packaging box according to claim 1, characterized in that the inclined surface portion is demarcated by the edge of the side opening and the pair of V-shaped fold lines.

3. The aforementioned locking piece is, A hinge portion (40) is formed between a pair of notches (42) cut into the upper side of one of the pair of first side walls and is connected to the other first side wall via a first locking fold line (L8), The hinge portion has a locking body portion (41) connected to the tip of the hinge portion via a second locking fold line (L9) and inserted into the locking hole, A pair of notches (44) are recessed into the base end of the locking body portion, with both ends approaching each other. The packaging box according to claim 2, characterized in that, with the locking body inserted into the locking hole, the pair of inclined surfaces fit into the pair of notches.

4. The second locking fold line is bent or curved so as to protrude from both ends of the locking body toward the center in the lateral direction toward the hinge portion. The packaging box according to claim 3, characterized in that the locking body portion has a bent line (L10) formed therein so as to divide it into two equal parts in the horizontal direction.

5. The packaging box according to claim 4, characterized in that the opening body portion has a crescent-shaped opening with a lower edge (31A) that curves downward from a pair of side openings toward the center in the lateral direction.

6. The opening width (W2) of the opening body is set to be narrower than or equal to the distance (W5) between the pair of notches of the locking body. The opening width (W3) of the side opening is set to be wider than the depth (W6) of the notch in the locking body. The packaging box according to any one of claims 3 to 5, characterized in that the overall opening width (W1) of the locking hole is wider than or equal to the overall width (W4) of the locking body.

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