Cartons and carton blanks

Abstract

The invention relates to a carton, and discloses a carton and a carton blank that are not easy to break at corners. The carton blank includes a side wall blank surface that is used to enclose and form the side wall of the carton and is arranged in sequence, and a lap joint surface that is connected to the side wall blank surface at the tail end and is used to connect the head and tail side wall blank surfaces. Both sides of each side wall blank surface are respectively connected with a swing cover, and the swing covers on the same side are folded to form the bottom surface or the top surface of the carton. There are flaps that are connected to each other between adjacent swing covers on the same side, and there are also flaps that are connected between adjacent swing covers through the lap joint surface due to the lap joint relationship. A flap positive fold line is provided at the connection between each flap and one of the swing covers, and a flap reverse fold line is provided at the connection between each flap and another swing cover, and a through hole is provided at the intersection of the flap positive fold line and the flap reverse fold line. The carton is formed based on the above-mentioned carton blank. By changing the shape of the paper blank, a folding corner reinforcement structure is formed, which effectively improves the compressive strength of the carton without increasing the cost.

Description

Technical Field

[0001] The invention relates to a carton, in particular to a carton folding structure with enhanced corner compression strength. Background Art

[0002] At present, in the actual use of corrugated paper boxes, due to inappropriate logistics and transportation methods or other human factors, some paper boxes always have cracked corners and deformed paper boxes, affecting the packaging appearance and even transportation safety. By analyzing the cause of the problem and the structure and molding process of the paper box, the inventor found that the long and short flaps of ordinary corrugated paper boxes are separated by a die-cutting line. In the molding state, if the downward pressure exceeds the compressive strength of the paper box itself, it will cause the paper box to tear from the die-cutting line.

[0003] Is it possible to make this phenomenon happen less often through improvements?

[0004] The Chinese utility model patent "High Strength Carton" with the announcement number CN202130647U published on February 1, 2012 discloses a solution to this problem by providing a reinforcement member at each of the four inner corners of the bottom of the box body. The reinforcement member is an L-shaped piece, and its two faces are in contact with the two side faces of the box body. These reinforcement members are not connected to the carton body, so they are prone to displacement. In addition, the carton body and reinforcement members need to be made separately during production, which is inconvenient. Summary of the invention

[0005] In order to overcome the problem that the corners of existing cartons are prone to rupture, the technical problem to be solved by the present invention is to provide a carton and a carton blank that are not prone to rupture at the corners.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a carton blank comprises at least three side wall blanks arranged in sequence for enclosing and forming the side wall of the carton, and a lap joint surface connected to the side wall blank at the tail end for connecting the head and tail side wall blanks, both sides of each side wall blank are respectively connected with a swing cover, and the swing cover on the same side is folded to form the bottom surface or the top surface of the carton, a longitudinal positive fold line is provided between each side wall blank and the lap joint surface, and a transverse positive fold line is provided between each side wall blank and the swing covers on both sides thereof. Positive fold line, adjacent swing covers located on the same side are connected with first lapels, and the connection between the first lapels and two adjacent swing covers is respectively provided with fold lines of folding in opposite directions, namely, a positive fold line of the lapels and a reverse fold line of the lapels, and the swing cover at the tail end and the overlapping surface are connected with second lapels, and the connection between the second lapels and the swing cover / overlap surface is respectively provided with fold lines of folding in opposite directions, namely, a positive fold line of the lapels and a reverse fold line of the lapels, and through holes are provided at the intersections of the positive fold line of the lapels and the reverse fold line of the lapels.

[0007] The circumferential contour line of the through hole is a smooth curve.

[0008] The through hole is a cylindrical hole.

[0009] The diameter of the through hole is not less than twice the thickness of the carton blank.

[0010] The through hole is a variable diameter hole, the large diameter end of which is located on the outside of the carton after the carton bad side is folded, and the small diameter end is located on the inside of the carton after the carton bad side is folded, and the maximum diameter is not less than twice the thickness of the carton blank.

[0011] The first flap is located on one of the swing covers and is an integrated structure with the swing cover.

[0012] The second flap is located on the overlapping surface and is an integral structure with the overlapping surface.

[0013] There is a distance between the fold line of the second flap and the corresponding overlapping edge of the swing cover connected to the side wall blank of the head, and the distance is not less than the thickness of the carton blank.

[0014] The lengths of the front fold line of the lapel and the reverse fold line of the lapel are the same.

[0015] The length of the positive fold line of the flap is not less than twice the thickness of the carton blank and not greater than 1 / 3 of the width of the swing cover.

[0016] At least one of the front fold line of the flap and the reverse fold line of the flap is a discontinuous fold line.

[0017] The longitudinal positive fold line, the transverse positive fold line and the lapel reverse fold line are continuous fold lines, and the lapel positive fold line is a discontinuous fold line.

[0018] The present invention also provides a carton formed based on the carton blank. When the carton is folded and formed, the overlap surface needs to be fixedly connected to the side wall blank surface of the head.

[0019] The carton is a rectangular carton, has four side wall blanks, and the angle between the positive fold line of the flap and the negative fold line of the flap is 45°, wherein the positive fold line of the flap is located on the extension line of the longitudinal positive fold line on the carton blank.

[0020] The flap width of each flap is equal to 1 / 2 of the width of the carton, each first flap is an integral structure with the shorter flap, and each second flap is an integral structure with the overlap surface. The flap width refers to the distance from the corresponding transverse positive fold line to the top of the flap.

[0021] Furthermore, the shape of the shorter swing cover is approximately an isosceles trapezoid.

[0022] Furthermore, both sides of the short sides of the shorter flap are rounded to facilitate folding the shorter flap to the inner side of the longer flap.

[0023] Furthermore, the overlapped surface is connected to the side wall blank surface of the head by bonding or nailing.

[0024] The beneficial effects of the present invention are as follows: by changing the shape of the paper blank, a foldable corner reinforcement structure is formed, and a flap of appropriate size can increase the stress bending moment at the corner, absorb stress deformation, and enhance the compressive capacity of the carton. The through hole can absorb the thickness superposition of the corner, improve the stress conditions, and effectively improve the problem of corner damage in stacking, warehousing and logistics transportation of the carton, thereby improving the compressive strength of the carton. Moreover, the increase in compressive strength is achieved by changing the cutting shape of the carton blank, and basically does not increase the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of a carton blank according to Example 1 of the present invention.

[0026] Figure 2 yes Figure 1 A partial enlarged view of the middle J part.

[0027] Figure 3 yes Figure 1 A partial enlarged view of the middle K section.

[0028] Figure 4 Yes Figure 1 A schematic plan view of the overlapped surface being connected to the side wall blank of the head and then unfolded.

[0029] Figure 5 yes Figure 4 A partial enlarged view of the middle L part.

[0030] Figure 6 It is a schematic diagram of the forming process of the carton of Example 1 of the present invention (first state).

[0031] Figure 7 It is a schematic diagram of the forming process of the carton of Example 1 of the present invention (second state).

[0032] Figure 8 It is a schematic diagram of the structure of the carton of Example 1 of the present invention (closed state).

[0033] Fig. 9 It is a schematic diagram of a carton blank according to Example 2 of the present invention.

[0034] The markings in the figure are: 1-side wall blank, 2-lap surface, 3-swing cover, 4-rounded corner, 5-first flap, 6-through hole, 7-longitudinal positive fold line, 8-transverse positive fold line, 9-lap positive fold line, 10-lap reverse fold line, 11-A surface, 12-B surface, 13-C surface, 14-D surface, 15-second flap, 16-lap surface transverse positive fold line, 20-swing cover and flap overlap area, 30-lap surface and flap overlap area The overlapping area of ​​the flap is as follows: 31-A1 flap, 32-A flap, 33-B1 flap, 34-B flap, 35-C1 flap, 36-C flap, 37-D1 flap, 38-D flap, 40-flap, overlapping surface and flap, 51-A1 flap, 52-A flap, 53-B1 flap, 54-B flap, 55-C1 flap, 56-C flap, 57-D1 flap, 58-D flap. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0036] Example:

[0037] Take the application of the present invention on the most typical rectangular parallelepiped carton as an example.

[0038] like Figures 1 to 8 As shown, the side of the carton includes an A side 11, a B side 12, a C side 13, and a D side 14. The A side 11 is opposite to the C side 13, the B side 12 is opposite to the D side 14, and the overlapping surface 2 is connected to one end of the D side 14, which is used to connect the A side 11 and the D side 14 during molding. The two sides of the A side 11 are respectively an A rocker cover 32 and an A1 rocker cover 31, the two sides of the B side 12 are respectively a B rocker cover 34 and a B1 rocker cover 33, the two sides of the C side 13 are respectively a C rocker cover 36 and a C1 rocker cover 35, the two sides of the D side 14 are respectively a D rocker cover 38 and a D1 rocker cover 37, and the A side 11, B surface 12, C surface 13, and D surface 14 are collectively referred to as side wall blanks on the carton blank. There are longitudinal positive fold lines 7 between the side wall blanks and between the side wall blanks and the overlapping surfaces. There are transverse positive fold lines 8 between each side wall blank and the swing covers on both sides thereof. The width S2 of the overlapping surface 2 is smaller than the width S1 of the side wall blank at the head, i.e., the A surface 11. The height P2 of the overlapping surface 2 is greater than the height P1 of each side wall blank 1. There are also overlapping surface transverse positive fold lines 16 on both sides of the overlapping surface 2. The swing covers on both sides are folded to form the bottom and top surfaces of the carton.

[0039] like Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 5As shown, an A flap 52 for connection is provided at the root connection of the A flap 32 and the B flap 34, a B flap 54 for connection is provided at the root connection of the B flap 34 and the C flap 36, a C flap 56 for connection is provided at the root connection of the C flap 36 and the D flap 38, a D flap 58 for connection is provided at the root connection of the D flap 38 and the overlap surface 2, an A1 flap 51 for connection is provided at the root connection of the A1 flap 31 and the B1 flap 33, and a B1 flap 52 for connection is provided at the root connection of the B1 flap 33 and the C1 flap 35. A B1 flap 53 is provided at the root connection of the swing cover between the C1 swing cover 35 and the D1 swing cover 37, a C1 flap 55 is provided at the root connection of the swing cover between the D1 swing cover 37 and the overlap surface 2, wherein the A1 flap 51, A flap 52, B1 flap 53, B flap 54, C1 flap 55, and C flap 56 belong to the first flap 5, i.e., the flap connected between the swing covers, and the D1 flap 57 and D flap 58 belong to the second flap 15, i.e., the flap connected between the swing covers and the overlap surface. In this way, after being formed into a carton, the roots of the connection between the two adjacent swing covers are not completely separated, but become two parts connected to each other by folding the flaps. In fact, each flap is a structure integrated with the carton blank, and both the first flap 5 and the second flap 15 are part of the carton blank. In other words, from the extension direction of the longitudinal positive fold line of the carton blank, the six first flaps 5 can be regarded as part of the swing cover, and the two second flaps 15 can be regarded as part of the overlapping surface.

[0040] In this embodiment, the A flap 52 is an integrated structure with the A swing cover 32, the B flap 54 and the C flap 56 are an integrated structure with the C swing cover 36, the A1 flap 51 is an integrated structure with the A1 swing cover 31, the B1 flap 53 and the C1 flap 55 are an integrated structure with the C1 swing cover 35, that is, the first flap 5 is an integrated structure with the shorter swing cover, and the D1 flap 57 and the D flap 58 are located on the overlapping surface 2 and are an integrated structure with the overlapping surface 2.

[0041] In the present embodiment, the shape of each flap is an isosceles triangle. According to the present invention, the flap contour line between the two end points of the flap positive fold line 9 and the flap reverse fold line 10 of the flap that are separated from each other can also be other lines other than a straight line.

[0042] In this embodiment, each flap is provided with a flap positive fold line 9 and a flap reverse fold line 10 of equal length. Since the carton has thickness, through holes 6 (i.e. holes 61 to 68 shown in the figure) are provided at the intersection of the flap positive fold line 9 and the flap reverse fold line 10. The purpose of opening the through holes 6 is twofold. One is to absorb the superposition of the carton thickness caused by folding, to avoid forming sharp corners when folding the flaps, and to avoid scratching and pricking the hands. If there are no such holes, when the thickness of the carton blank is particularly thick, it may not even be folded into shape; the other is equivalent to chamfering the intersection of the edges of the carton. When the carton is pressed or hit, the force at the corner will change from the "point force" of the intersection of the edges of the conventional carton to the "surface force" of the hole wall of the through hole 6 in this embodiment. Therefore, although the holes are opened, under the same other conditions, the breakage rate can be reduced. It is recommended that the diameter of the through hole 6 be as small as possible while ensuring folding and forming without forming sharp corners. It is usually not recommended that the maximum aperture of the through hole 6 exceed 4 times the thickness of the carton blank. Too large an aperture will affect the corner strength and cause the carton to easily enter with water. The through hole 6 is preferably a hole whose circumferential contour line is a smooth curve, especially a cylindrical hole, a conical hole, or an elliptical cylinder hole, etc., which is easy to process and does not easily form a stress concentration point around the opening. In this embodiment, the through hole 6 is a cylindrical hole, and its aperture is equal to twice the thickness of the carton blank. If the through hole 6 is a variable diameter hole, the aperture on the outer side of the carton after folding is larger than the aperture on the inner side of the carton after folding, so that the holes at the corners can form a "shrinkage" effect as the folding is formed, making it difficult for water to enter the carton.

[0043] After the carton blank with the above flap and through-hole structure is formed, the carton corners have flaps. When subjected to pressure or tension, the flaps can play a protective role, increase the bending moment at the corners of the carton, increase the compressive strength of the carton, and absorb the stress deformation of the carton in certain stress directions. It is no longer easy to tear at the intersection of the edges of the carton like traditional cartons.

[0044] In this embodiment, because the adjacent flaps are 90° apart after folding, the flap inverse fold line 10 is a reverse indentation with an angle of 45° relative to the flap positive fold line 9 .

[0045] If the lengths of the flap positive fold line 9 and the flap reverse fold line 10 are the same, a neat isosceles flap angle is formed after the flap is folded, but the purpose of the invention does not require that the lengths of the two must be equal. After folding, the thickness of the cardboard at the overlapping area 20 of the swing cover and the first flap 5 is three times the thickness of the carton blank, that is, the thickness of the two layers of the swing cover plus the thickness of the first flap 5.

[0046] According to the above purpose, considering that the carton blank must have a certain thickness, especially the carton with higher strength requirements, the length of the flap positive fold line 9 is not less than twice the thickness of the carton blank and not more than 1 / 3 of the swing cover width. A flap that is too small will only have a limited effect on the improvement of strength. In theory, the maximum length of the flap positive fold line 9 can be equal to the swing cover width, but according to the experiments recorded later, a flap that is too large may have a counter-effect on the improvement of the compressive strength of the carton.

[0047] like Figure 4 and Figure 5 As shown, also considering the thickness of the carton blank, in order to make it folded and formed smoothly, the area where the second flap 15 is located is not designed as an overlapping area, and there is a spacing d between the flap inversion line 10 of the second flap 15 and the corresponding overlapping edge of the swing cover 32 connected to the A surface 11 of the head, and the spacing d is not less than the thickness of the carton blank. After the overlapping surface 2 and the A surface 11 are completed, the overlapping surface 2 can be regarded as a part of the A surface 11. At this time, the second flap 15 is equivalent to the second flap 15 connected between adjacent swing covers. The thickness of the first flap 5 and the second flap 15 is equal to the thickness of the first flap 5 and equal to the thickness of the carton blank, except that the cardboard thickness in the overlapping area is thicker. The thickness of the cardboard in the overlapping area 30 between the overlapping surface and the flap is twice the thickness of the carton blank, that is, the thickness of the swing cover here is equivalent to the thickness of two layers of the carton blank. After folding, the thickness of the cardboard in the overlapping area 40 between the swing cover, the overlapping surface and the second flap 15 is four times the thickness of the carton blank, that is, the thickness of the two layers of the swing cover plus the thickness of the second flap 15.

[0048] like Figure 1 , Figure 7 , Figure 8 As shown, by folding the first flap 5 and the second flap 15, the longer B flap 34 and D flap 38 cover the shorter A flap 32 and C flap 36, and the longer B1 flap 33 and D1 flap 37 cover the shorter A1 flap 31 and C1 flap 35; the first flap 5 and the second flap 15 can also be folded to make the shorter A flap 32 and C flap 36 cover the longer B flap 34 and D flap 38, and the shorter The A1 flap 31 and C1 flap 35 cover the longer B1 flap 33 and D1 flap 37. The longer B1 flap 33, B flap 34, D1 flap 37 and D flap 38 are rectangular in shape. The shorter A1 flap 31, A flap 32, C1 flap 35 and C flap 36 are approximately isosceles trapezoidal in shape and the short sides of the trapezoid away from the side wall blank surface are rounded 4. The rounded corners 4 on the shorter flap make it easier to fold and form. The "long" and "short" mentioned here actually refer to Figure 1 The lengths of the swing covers are M1 and M2, M1>M2. In this embodiment, all the swing covers have the same width N.

[0049] In addition, since the paperboard has a certain thickness, in this embodiment, in order to facilitate molding, the longitudinal positive fold line 7, the transverse positive fold line 8, and the flap reverse fold line 10 are continuous fold lines, and the flap positive fold line 9 is a discontinuous fold line.

[0050] Under the condition that the connection strength is guaranteed, the positive fold line 9 and the reverse fold line 10 of the lapel can also be discontinuously cut, and a toothed knife or a die-cutting line cutter can be used to partially cut and partially connect the fold lines, so as to form discontinuous fold lines.

[0051] In this embodiment, the overlapping surface 2 is bonded to the A surface 11 , and the overlapping surface 2 is located on the inner surface of the A surface 11 .

[0052] In this embodiment, cartons of various sizes but of the same material are selected for comparative compression test. The comparison objects are conventional cartons with the same outer dimensions and the cartons of this embodiment with flaps and through holes. According to the national standard GB-T4857.4, the results of the empty box compression test are shown in the following table.

[0053] Table 1 Comparison of compression tests

[0054]

[0055]

[0056] It can be seen from Table 1 that by connecting flaps of appropriate size between the flaps and opening holes at the corners, the compressive strength of the carton can be increased by an average of 11.9%. The flap sizes that can maximize the compressive strength for cartons of various sizes can be obtained by referring to the above experiments.

[0057] This embodiment uses a rectangular carton as an example to illustrate the present invention. In fact, for special-shaped carton boxes such as triangular prisms and octagonal prisms, the foldable flap design can also be used to achieve similar effects and purposes as this embodiment, strengthen the connection strength of the corners of the carton, thereby improving the compressive strength of the carton as a whole, and does not increase the cost. In addition, the solution of only providing flaps on one side of the side wall blank instead of both sides to increase the compressive strength of only the bottom or top surface is a solution equivalent to this embodiment.

[0058] Embodiment 2:

[0059] like Fig. 9As shown, each first flap 5 is an integral structure with the longer swing cover, and the second flap 15 is an integral structure with the swing covers 3 on both sides of the side wall blank surface 1 at the tail end. At this time, a flap inverse fold line 10 is provided between the second flap 15 and the corresponding swing cover, and a flap positive fold line 9 is provided at the connection between the second flap 15 and the overlapping surface 2. The through hole 6 at the intersection of each flap positive fold line 9 and the flap inverse fold line 10 is a conical hole, the large end diameter of which is equal to twice the thickness of the carton blank, and the small end diameter is equal to the thickness of the carton blank, and the rest is the same as Example 1.

[0060] In the figure, M1 is the length of the carton after molding, M2 is the width of the carton after molding, N is the width of the longer flap, N2 is the width of the shorter flap, and N2 is 1 / 2 of M1.

Claims

1. A carton blank, comprising at least three side wall blanks (1) arranged in sequence for enclosing and forming a carton side wall, and an overlap surface (2) connected to the side wall blank (1) at the tail end for connecting the head and tail side wall blanks (1), both sides of each side wall blank (1) are respectively connected with a swing cover (3), the swing cover (3) on the same side is folded to form the bottom surface or top surface of the carton, longitudinal positive fold lines (7) are provided between each side wall blank (1) and between the side wall blank (1) and the overlap surface (2), and transverse positive fold lines (8) are provided between each side wall blank (1) and the swing covers (3) on both sides thereof, wherein: Adjacent swing covers (3) located on the same side are connected to each other by first flaps (5), and the connection between the first flap (5) and the two adjacent swing covers (3) is respectively provided with flap fold lines folded in opposite directions, namely, a flap positive fold line (9) and a flap reverse fold line (10). A second flap (15) is connected to each other between the swing cover (3) and the overlap surface (2), and the connection between the second flap (15) and the swing cover (3) / overlap surface (2) is respectively provided with flap fold lines folded in opposite directions, namely, a flap positive fold line (9) and a flap reverse fold line (10). A through hole (6) is provided at the intersection of the flap positive fold line (9) and the flap reverse fold line (10), the through hole (6) being a variable diameter hole, the large diameter end of which is located on the outside of the carton after the carton blank is folded, and the small diameter end of which is located on the inside of the carton after the carton blank is folded, and the maximum diameter of which is not less than twice the thickness of the carton blank and not more than four times the thickness of the carton blank, and there is a spacing d between the flap reverse fold line (10) of the second flap (15) and the corresponding overlapping edge of the rocker cover (32) connected to the side wall blank (1) of the head, and the spacing d is not less than the thickness of the carton blank.

2. The carton blank according to claim 1, characterized in that: The first flap (5) is located on one of the swing covers (3) and is an integral structure with the swing cover (3).

3. The carton blank according to claim 1, characterized in that: The second flap (15) is located on the overlapping surface (2) and is an integral structure with the overlapping surface (2).

4. The carton blank according to claim 3, characterized in that: There is a distance (d) between the flap fold line (10) of the second flap (15) and the corresponding overlapping edge of the swing cover (3) connected to the side wall blank (1) of the head, and the distance (d) is not less than the thickness of the carton blank.

5. The carton blank according to any one of claims 1 to 4, characterized in that: The length of the front fold line (9) of the flap is the same as the length of the back fold line (10) of the flap.

6. The carton blank according to claim 5, characterized in that: The length of the positive fold line (9) of the flap is not less than twice the thickness of the carton blank and not greater than 1 / 3 of the width of the swing cover (3).

7. The carton blank according to any one of claims 1 to 4, characterized in that: At least one of the flap positive fold line (9) and the flap reverse fold line (10) is a discontinuous fold line.

8. The carton blank according to any one of claims 1 to 4, characterized in that: The longitudinal positive fold line (7), the transverse positive fold line (8), and the flap reverse fold line (10) are continuous fold lines, and the flap positive fold line (9) is a discontinuous fold line.

9. A carton made from the carton blank according to any one of claims 1 to 4.

10. The carton according to claim 9, characterized in that: The carton is a rectangular carton, the side wall blank surface (1) has four sides, the angle between the flap positive fold line (9) and the flap reverse fold line (10) is 45 degrees, wherein the flap positive fold line (9) is located on the extension line of the longitudinal positive fold line (7) on the carton blank surface.

11. The carton according to claim 10, characterized in that: The swing flap width of each swing flap (3) is equal to 1 / 2 of the width of the carton, each first flap (5) is an integral structure with the shorter swing flap (31), and each second flap (15) is an integral structure with the overlap surface (2).

12. The carton according to claim 11, characterized in that: The shorter rocker cover (3) is in the shape of an isosceles trapezoid.

13. The carton according to claim 12, characterized in that: The shorter sides of the shorter flap are rounded.

14. The carton according to claim 9, characterized in that: The overlapping surface (2) is connected to the side wall blank surface (1) of the head by bonding or nailing.

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