Laminated corrugated board sheet and manufacturing method

Abstract

To provide a laminated corrugated board sheet that is easier to bend.SOLUTION: A laminated corrugated board sheet comprises: 3 or more liners 21-24; 2 or more middle cores 31-33; and a fold 4 formed on a surface liner 21 which extends in a prescribed direction. The fold 4 includes a notch 41 formed by cutting the surface liner 21, which extends in the prescribed direction, and a one-side ruled line 42 formed by the surface liner 21 being pressed to one side of the notch 41, which extends in parallel to the notch 41 such that a portion overlaps the notch 41. The notch 41 is formed deeper than the one-side ruled line 42. In an orthogonal cross section of the fold, which is the cross section made by cutting the fold 4 on a virtual plane orthogonal to a virtual straight line extending in the prescribed direction, an angle θ1 of a rear face side formed by the notch 41 and the one-side ruled line 42 is less than 90 degrees.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a laminated corrugated cardboard sheet having multiple layers and a method for manufacturing the same. [Background technology]

[0002] Laminated corrugated cardboard sheets, which are made up of multiple layers, are superior to single-layer corrugated cardboard sheets in terms of strength and durability. For example, a two-layer laminated corrugated cardboard sheet consists of a surface liner, a back liner, an intermediate liner placed between the surface liner and the back liner, and a corrugated core placed between each liner. In other words, a laminated corrugated cardboard sheet consists of three or more liners and two or more cores.

[0003] Hereinafter, in a laminated cardboard sheet, the direction in which the corrugations formed by the corrugation medium extend (the direction along the corrugations) is referred to as the longitudinal direction, and the direction perpendicular to the corrugations on the surface liner is referred to as the transverse direction. For example, if a longitudinal crease is formed in the surface liner, when attempting to bend the laminated cardboard sheet so that the surface liner faces inward, the bending position may be off due to factors such as the position of the irregularities in the corrugation medium or the shape of the creases. To address this issue, for example, a crease forming device described in JP-A-8-150675 forms wedge-shaped openings and cuts on the surface of the laminated cardboard sheet. With this crease, the position of the cut ensures accuracy in the bending position, and the wedge shape prevents excessive crushing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-150675 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while the above-mentioned creases raise the issue of accuracy in the bending position, they do not take into consideration ease of folding, particularly along horizontal creases. While the accuracy of the bending position is important when folding a laminated cardboard sheet, as described above, ease of bending (e.g., less slippage or reduced labor) is also important. With conventional crease configurations, folding a laminated cardboard sheet neatly along a crease requires relatively difficult work, such as applying a uniform force along the crease using a specialized jig. Bending a laminated cardboard sheet 1 neatly along a crease requires considerable bending force, skill, or specialized tools, making it difficult for average users. This is particularly difficult for horizontal creases.

[0006] An object of the present invention is to provide a laminated cardboard sheet that can improve bendability, and a method for manufacturing the same. [Means for solving the problem]

[0007] A laminated cardboard sheet according to a first embodiment of the present invention is a laminated cardboard sheet including three or more liners, two or more cores, and a crease formed on the liner on the surface, extending in a predetermined direction, wherein the crease comprises a notch extending in the predetermined direction formed by cutting the liner on the surface, and a one-side crease formed by pressing the liner on the surface to one side of the notch, extending parallel to the notch so as to overlap partially with the notch, wherein the notch is formed deeper than the one-side crease, and in a crease perpendicular cross section, which is a cross section of the crease cut by an imaginary plane perpendicular to an imaginary straight line extending in the predetermined direction, the angle on the back side formed by the notch and the one-side crease is less than 90 degrees.

[0008] A second aspect of the present invention is a laminated cardboard sheet comprising three or more liners, two or more cores, and creases formed on the surface of the liners in a predetermined direction, wherein the creases comprise recesses formed on the surface and extending in the predetermined direction, one or more notches formed within the recesses so as to extend in the predetermined direction, and one or more creases formed within the recesses so as to extend parallel to the notches, wherein the notches are formed deeper than the creases by cutting the surface liner, and the creases are formed deeper than the recesses by pressing the surface liner.

[0009] The manufacturing method of the present invention is a manufacturing method for manufacturing a second type of laminated cardboard sheet using a crease forming device that includes a blade portion for forming the incisions, a pressing portion for forming the creases, a drive portion for driving the blade portion and the creases, and wide portions formed at the base of the blade portion and the pressing portion, and includes an incision forming process for forming the incisions with the blade portion, and a crease forming process for forming the creases with the pressing portion, and the recesses are formed by the wide portions at least in the crease forming process. [Effects of the Invention]

[0010] According to the first aspect of the present invention, the angle between the incision that forms the fold and the one-side crease is an acute angle. This distributes the bending force between the incision and the one-side crease during the bending process. This allows for gradual bending, reduces the likelihood of the bending force escaping to areas other than the crease, and reduces the likelihood of the bend shifting from the crease. In other words, this crease makes the worker feel that the bending is easy. As a result, it is possible to reduce the amount of bending force required. Furthermore, because the incision is formed deeper than the one-side crease, the accuracy of the final folding position is maintained. Even for folds that extend horizontally and are difficult to bend, the ease of folding is improved if the angle between the incision and the one-side crease is 120 degrees or less, or even 90 degrees or less, due to the reduced likelihood of shifting and the roughly concentrated bending force.

[0011] According to a second aspect of the present invention, a cut and a crease are formed within a single recess. During bending, the recess determines the approximate bending position, and the bending force is concentrated in the recess while being dispersed to multiple points of application by the crease and the cut. This allows for gradual bending, making it difficult for the bending force to escape to areas other than the crease, and making it difficult for the bend to deviate from the crease. In other words, this crease makes the worker feel that bending is easy. As a result, it is also possible to reduce the amount of bending force required. Furthermore, because the cut is formed deeper than the crease, the accuracy of the final bending position is maintained.

[0012] According to the manufacturing method of the present invention, recesses are formed as a secondary process when the scores are formed, so that the second type of laminated corrugated cardboard sheet, which is easy to bend, can be easily formed. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a conceptual diagram showing a side view of a laminated cardboard sheet of the present embodiment viewed in the vertical direction. [Figure 2] FIG. 2 is a conceptual diagram showing a plan view of the laminated cardboard sheet of the present embodiment. [Figure 3] 1 is a conceptual diagram showing a side (cross section) of a portion of a laminated cardboard sheet of a first embodiment as viewed from the lateral direction. [Figure 4] FIG. 4 is a conceptual diagram corresponding to FIG. 3, illustrating a modified embodiment of the first embodiment. [Figure 5] FIG. 10 is a conceptual diagram showing a side (cross section) of a portion of a laminated cardboard sheet of a second embodiment as viewed from the lateral direction. [Figure 6] FIG. 6 is a conceptual diagram corresponding to FIG. 5, illustrating a modified embodiment of the second embodiment. [Figure 7] FIG. 6 is a conceptual diagram corresponding to FIG. 5, illustrating a modified embodiment of the second embodiment. [Figure 8] 1 is a conceptual diagram showing a laminated cardboard sheet having a plurality of folds according to an embodiment of the present invention. [Figure 9] FIG. 8 is a conceptual diagram showing the laminated cardboard sheet of FIG. 7 after being folded. [Figure 10]1 is a conceptual diagram showing the laminated cardboard sheet of the present embodiment after being folded at a right angle. FIG. [Figure 11] FIG. 10 is a conceptual diagram illustrating an example of a fold forming device. [Figure 12] FIG. 4 is a conceptual diagram corresponding to FIG. 3 of a modified embodiment of the first embodiment. [Figure 13] FIG. 10 is a conceptual perspective view showing a part of a modified embodiment of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, as a mode for carrying out the present invention, a laminated cardboard sheet 1, which is one embodiment of the present invention, will be described in detail with reference to the drawings. In addition to the following examples, the present invention can be carried out in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

[0015] As an example, a three-layer laminated cardboard sheet will be described. The cuts can be formed using a known crease forming device that can control the blade position, for example. The creases can be formed using a known crease forming device that can control the position of the pressing part, for example.

[0016] First Embodiment 1 and 2, the laminated corrugated cardboard sheet 1 includes a surface liner 21, a back liner 22, intermediate liners 23 and 24, corrugated cores 31, 32 and 33, and a fold 4 formed in the surface liner 21. The liners 21 to 24 are sheet-like members.

[0017] The surface liner 21 forms one surface in the thickness direction of the laminated corrugated cardboard sheet 1. The back liner 22 forms the other surface in the thickness direction of the laminated corrugated cardboard sheet 1. The intermediate liners 23 and 24 are arranged between the surface liner 21 and the back liner 22. The liners 21 to 24 are arranged parallel to each other.

[0018] The core 31 is disposed between the surface liner 21 and the intermediate liner 23. The core 32 is disposed between the intermediate liner 23 and the intermediate liner 24. The core 33 is disposed between the intermediate liner 24 and the back liner 22. Each of the cores 31 to 33 is disposed between two of the liners 21 to 24. The liners 21 to 24 and the cores 31 to 33 are bonded together.

[0019] The first layer 51 is formed by the surface liner 21, the core 31, and the intermediate liner 23. The second layer 52 is formed by the intermediate liner 23, the core 32, and the intermediate liner 24. The third layer 53 is formed by the intermediate liner 24, the core 33, and the back liner 22. In this example, the thickness of each of the layers 51 to 53 is uniform. In this example, the thickness of each of the liners 21 to 24 is the same as one another, and the thickness of each of the cores 31 to 33 is the same as one another. The laminated cardboard sheet 1 of this embodiment is a so-called reinforced cardboard sheet.

[0020] As shown in Figure 2, corrugations (only some of which are shown) are formed in the laminated cardboard sheet 1 by the corrugated shapes of the cores 31-33. The extension direction of the corrugations (the direction along the corrugations) is the "longitudinal direction," and the direction perpendicular to the corrugations on the surface liner 21 is the "lateral direction." Figure 1 is a view of the side of the laminated cardboard sheet 1 viewed in the longitudinal direction. Figure 3 is a view of the side of the laminated cardboard sheet 1 viewed in the lateral direction.

[0021] The fold line 4 extends in a predetermined direction on the surface liner 21. In this embodiment, the predetermined direction is the horizontal direction. The fold line 4 extends linearly (or in the form of a dashed line) from one horizontal end of the laminated cardboard sheet 1 to the other horizontal end. The laminated cardboard sheet 1 is folded with the fold line 4 as a reference so that the surface liner 21 faces inward (see FIG. 10). In other words, the laminated cardboard sheet 1 is folded so that the left and right ends in FIG. 3 move upward during the bending operation.

[0022] As shown in FIG. 3 , the fold 4 is composed of a notch 41, a one-side crease 42, and an other-side crease 43. The notch 41 is formed by cutting at least the surface liner 21. In this embodiment, the notch 41 is formed by cutting the surface liner 21 and the intermediate liners 23 and 24. That is, the notch 41 is formed up to the third layer 53. The tip (bottom) of the notch 41 reaches the middle position of the third layer 53. The notch 41 extends linearly in the horizontal direction. The notch 41 is formed deeper than the one-side crease 42 and the other-side crease 43.

[0023] The one-side crease 42 is formed by pressing the surface liner 21 on one vertical side of the incision 41. The one-side crease 42 extends parallel to the incision 41 so as to partially overlap the incision 41. The side of the one-side crease 42 and the side of the incision 41 are in contact with each other. The one-side crease 42 and the incision 41 are integrated, and no flat portion of the surface liner 21 exists between them. The one-side crease 42 extends linearly in the horizontal direction. The one-side crease 42 is formed by squeezing the first layer 51 (the surface liner 21 and the core 31). The one-side crease 42 is formed within the first layer 51. In other words, the tip (bottom) of the one-side crease 42 is located within the first layer 51. In this disclosure, a "incision" is formed by cutting the object to be formed, while a "crease" is formed by pressing (squashing) the object to be formed without cutting it.

[0024] The other-side crease 43 is formed by pressing the surface liner 21 on the other vertical side of the incision 41. The other-side crease 43 extends parallel to the incision 41 so as to partially overlap the incision 41. The side of the other-side crease 43 contacts the side of the incision 41. The other-side crease 43 and the incision 41 are integrated, and no flat portion of the surface liner 21 exists between them. The other-side crease 43 extends linearly in the horizontal direction. Like the one-side crease 42, the other-side crease 43 is formed by compressing the first layer 51 (the surface liner 21 and the core 31). The other-side crease 43 is formed within the first layer 51. In other words, the tip (bottom) of the other-side crease 43 is located within the first layer 51. In this embodiment, the one-side crease 42 and the other-side crease 43 are formed symmetrically with respect to the incision 41. It can be said that the fold 4 is formed symmetrically with the cut 41 as the center.

[0025] Hereinafter, a cross section cut along the fold 4 by an imaginary plane perpendicular to an imaginary line extending in the horizontal direction will be referred to as a "cross section perpendicular to the fold." Figure 3 is a side view of the laminated cardboard sheet 1 viewed in the horizontal direction, but its shape corresponds to a cross section perpendicular to the fold. For example, the side view of the laminated cardboard sheet 1 viewed in the direction of the fold and the cross section perpendicular to the fold have the same shape.

[0026] In the cross section perpendicular to the fold, the angle θ1 on the back surface formed between the incision 41 and the one-side crease 42 is less than 90 degrees (an acute angle). Similarly, in the cross section perpendicular to the fold, the angle θ2 on the back surface formed between the incision 41 and the other-side crease 43 is less than 90 degrees (an acute angle). In other words, the angles (intersection angles) θ1 and θ2 formed between the side of the incision 41 and the side of each crease 42, 43 on the back surface are acute angles. As a result, convex portions (protruding portions) 44, 45 are formed on both sides of the incision 41 in the width direction (vertical direction). The tips of the convex portions 44, 45 are located closer to the back surface than the portion of the surface liner 21 where the crease 4 is not formed. When the intersection angles θ1 and θ2 are less than 90 degrees, convex portions 44 and 45 are formed, and the bottoms (deepest portions) of the creases 42 and 43 are separated in the width direction (longitudinal direction) from the bottoms (deepest portions) of the cuts 41. This allows the bending force to be dispersed appropriately.

[0027] According to the first embodiment, the intersection angles θ1 and θ2 between the incision 41 and the creases 42 and 43 that make up the fold 4 are acute. This causes the bending force to act at three locations: the incision 41 and the creases 42 and 43. The bending force is generally concentrated at the incision 41, but is dispersed across the convex portions 44 and 45. This allows for gradual bending (deformation) at the incision 41 and the creases 42 and 43, making it difficult for the bending force to escape to areas other than the crease 4 and reducing deviation from the crease 4. In other words, this crease 4 allows the worker to feel that bending is easy. This also results in reduced bending force. Furthermore, because the incision 41 is formed deeper than the creases 42 and 43, the accuracy of the final bending position is maintained.

[0028] 4, the fold 4 may also include a first-side sub-crease 46 extending parallel to the first-side crease 42 on one longitudinal side of the first-side crease 42 so as to partially overlap the first-side crease 42, and a second-side sub-crease 46 extending parallel to the second-side crease 43 on the other longitudinal side of the second-side crease 43 so as to partially overlap the second-side crease 43. The creases 46 and 47 are shallower than the creases 42 and 43. This also improves the ease of bending, including reducing the bending force required. Following the creases 46 and 47, one or more creases may be formed parallel to the first-side crease 42 and / or the second-side crease 43 so as to partially overlap each other.

[0029] The number of overlapping creases is set by taking into consideration, for example, the specific characteristics of the laminated cardboard sheet 1 (e.g., difficulty in bending, high strength), the bending position (e.g., center or edge of the sheet), and the shape after bending (e.g., curved shape, right-angled shape). If the number of creases (including creases 42 and 43) on both sides of the cut 41 is the same, the laminated cardboard sheet 1 can be folded in a balanced manner around the cut 41. Furthermore, if it is desired to distribute more force to one side of the cut 41, for example, there may be more creases on one side of the cut 41 than on the other side. In other words, the number of creases on both sides of the cut 41 may be different.

[0030] Second Embodiment As shown in Fig. 5, the laminated cardboard sheet 1 of the second embodiment includes a surface liner 21, a back liner 22, intermediate liners 23 and 24, and a fold 40 formed on the surface liner 21 so as to extend laterally. As with the first embodiment, the fold 40 is a fold for folding the surface liner 21 so that it faces inward. The configuration of the second embodiment differs from the first embodiment only in the configuration of the fold, and therefore only the fold will be described.

[0031] The fold 40 includes a recess 40a, a notch 401, a one-side crease 402, and an other-side crease 403. The recess 40a is formed in the surface liner 21 and extends in the horizontal direction. The recess 40a is formed by pressing the surface liner 21. The width of the recess 40a is the width of the fold 40.

[0032] The recesses 40a can be formed by a known crease forming device having a pressing unit. The crease forming device includes, for example, a pressing unit capable of pressing the surface liner 21 and a drive unit that controls the position of the pressing unit. The recesses 40a may be formed as (1) a single wide, long groove, or (2) a plurality of narrow, long grooves extending in parallel and overlapping each other. In the case of (1), for example, one recess 40a may be formed in the surface liner 21 in advance, and the incisions 401 and the creases 402 and 403 may be formed inside it.

[0033] In the case of (2) above, the recesses 40a may be formed secondarily when the incisions 401 and / or the creases 402, 403 are formed, for example, by the pressing portion or the base portion (wide portion) of the blade pressing against the surface liner 21. In this way, the recesses 40a may be formed by a plurality of long grooves extending in the horizontal direction and arranged in parallel so as to partially overlap each other.

[0034] The notch 401 is formed in the recess 40a so as to extend in the horizontal direction (corresponding to the predetermined direction). The notch 401 is formed deeper than the one-side crease 402 and the other-side crease 403 by cutting at least the surface liner 21. The notch 401 in this embodiment reaches the third layer 53. The notch 41 extends linearly in the horizontal direction.

[0035] The one-side crease 402 is a crease formed to extend parallel to the incision 41. The one-side crease 402 is formed on one side in the vertical direction of the incision 41. The one-side crease 402 is formed deeper than the recess 40a by pressing the front surface liner 21. The one-side crease 402 is formed spaced apart from the incision 401 in the width direction (vertical direction).

[0036] The other-side crease 403 is a crease formed to extend parallel to the incision 41. The other-side crease 403 is formed on the other side in the vertical direction of the incision 41. The other-side crease 403 is formed deeper than the recess 40a by pressing the front surface liner 21. The other-side crease 403 is formed spaced apart from the incision 401 in the width direction (vertical direction).

[0037] The depths of the various portions are, in descending order, the incision 401, the creases 402 and 403, and the recess 40a. The one-side crease 402 and the other-side crease 403 are formed symmetrically with respect to the incision 401. More specifically, the fold 40 is formed symmetrically with respect to the incision 401.

[0038] As described above, the fold 40 is formed by forming the incision 401 and the two creases 402 and 403 within the recess 40a. During the bending process, the recess 40a determines the approximate bending position, and the bending force is concentrated in the recess 40a and dispersed to multiple points of application by the creases 402 and 403 and the incision 401. This allows for gradual bending, making it difficult for the bending force to escape to areas other than the fold 40, and preventing the bending from deviating from the fold 40. In other words, this fold 40 allows the worker to feel that bending is easy. As a result, it is also possible to reduce the amount of bending force required. Furthermore, because the incision 401 is formed deeper than the creases 402 and 403, the accuracy of the final bending position is maintained.

[0039] In the second embodiment, the distance d1 between the incision 401 and the one-side crease 402 is smaller than the thickness of each layer 51, 52, 53 of the laminated cardboard sheet 1. More specifically, the distance d1 between one longitudinal end of the incision 401 and the other longitudinal end of the one-side crease is smaller than the thickness of each of the corrugations 31, 32, 33. The same applies to the distance between the incision 401 and the other-side crease 403. As an example, the thickness of each of the layers 51, 52, 53 of the laminated cardboard sheet 1 (the thickness of the corrugations) is 5 mm, and the distance d1 between the incision 401 and the one-side crease 402 is 3 mm. The small distance d1 encourages the bending force to be roughly concentrated on the incision 401, further improving the ease of bending. When the thicknesses of the layers (corrugations) are different, the distance d1 may be equal to or smaller than the thinnest layer, for example.

[0040] As shown in Fig. 6, one-side crease 402 and other-side crease 403 may extend parallel to slit 401 so as to partially overlap slit 401. This also improves the ease of bending, as described above. In the configuration of Fig. 6, crossing angles θ3 and θ4 are preferably 120 degrees or less. Furthermore, as shown in Fig. 7, crossing angles θ3 and θ4 are preferably 90 degrees or less, and even less than 90 degrees.

[0041] Furthermore, the fold 40 may have one or more creases (one-side sub-creases) formed in the recess 40a on one side in the vertical direction of the one-side crease 402. Similarly, the fold 40 may have one or more creases (other-side sub-creases) formed in the recess 40a on the other side in the vertical direction of the other-side crease 403. Furthermore, the fold 40 may have a plurality of notches 401 in the recess 40a. <Example of common features between the first and second embodiments> In this embodiment, the width (length in the vertical direction) of the folds 4, 40 is greater than the thickness of the laminated cardboard sheet 1. For example, the length from one vertical end of the one-side crease 42 to the other vertical end of the other-side crease 43, or the length between both vertical ends of the recess 40a, is greater than the length from the front to the back of the laminated cardboard sheet 1. This allows stable folding even for a laminated cardboard sheet 1 with high strength.

[0042] The depth of the cuts 41 and 401 is more than half the thickness of the laminated cardboard sheet 1, and the depth of each of the creases 42, 43, 402, and 403 is less than half the thickness of the laminated cardboard sheet 1. More specifically, the cuts 41 and 401 are formed to reach the layer 53 closest to the back surface, and each of the creases 42, 43, 402, and 403 is contained within the layer 51 closest to the front surface. In other words, the cuts 41 and 401 are formed to reach the intermediate liner 24, which is the second liner from the back surface, and each of the creases 42, 43, 402, and 403 is formed so as not to reach the intermediate liner 23, which is the second liner from the front surface. This more effectively utilizes the positioning effect of the cuts 41 and 401, and the relatively shallow creases 42, 43, 402, and 403 improve bendability while maintaining strength at the bending portion.

[0043] In a laminated cardboard sheet having three (or more) layers of the same thickness, a configuration in which the incisions are formed to reach the layer closest to the back surface and the creases are contained within the layer closest to the front surface is an example of a suitable configuration. When applying the term "reaching" to the example of this embodiment, if the incisions 41, 401 cut at least a portion of the intermediate liner 24, or if the core 32 in contact with the front surface side of the intermediate liner 24 is cut from one end to the other in the thickness direction, it can be said that the incisions 41, 401 reach the intermediate liner 24 or the layer closest to the back surface. A configuration in which the incisions 41, 401 are contained within the layer 52, which is second from the back surface, is also preferred.

[0044] <Modifications of the First and Second Embodiments> (Configuration with only one ruled line) The folds 4, 40 may be formed only by the incisions 41, 401 and the one-side creases 42, 402, without the other-side creases 43, 403. Even with this configuration, the distribution of the bending force to two locations allows for gradual bending, resulting in an easier bending experience for the worker. This is also effective when uneven (asymmetric) force is required in the vertical direction when bending. However, by forming the creases 42, 43, 402, 403 symmetrically on both sides of the incisions 41, 401, misalignment of the bend can be more effectively prevented.

[0045] (Depth of cuts and creases) The depth of the incisions 41, 401 can be appropriately set depending on the bending angle, the required strength after bending, and other factors. For example, if emphasis is placed on post-bending strength, the incisions 41, 401 may be formed so that they do not reach the second liner 23 from the front surface. In other words, the incisions 41, 401 may be contained within the first layer 51. For example, if emphasis is placed on balancing the reduction in bending force and post-bending strength, the incisions 41, 401 may be formed so that they are contained within the second layer from the back surface (cutting the second core 32 from the back surface but not cutting the second liner 24 from the back surface). In other words, the incisions 41, 401 may be formed so that they do not reach the layer closest to the back surface (here, the third layer 53). This leaves only the layer closest to the back surface uncut, preserving the performance of the layer closest to the back surface and increasing strength. This configuration is effective, for example, for creases used to curve the laminated cardboard sheet 1. In this way, the depths of the cuts 41, 401, the one-side creases 42, 402, and the other-side creases 43, 403 are set taking into consideration the specific characteristics of the laminated cardboard sheet 1, the positions of the folds 4, 40, the bending shape, etc.

[0046] (intersection angle) In the first embodiment, even if the crossing angles θ1 and θ2 are 120 degrees or less, the angles are closer to 90 degrees than 180 degrees, which has the effect of roughly concentrating and dispersing bending force, making it possible to improve ease of bending. The crossing angles θ1 and θ2 may be 90 degrees or less. The same applies to the crossing angles θ3 and θ4 in the second embodiment.

[0047] (others) The folds 4, 40 may be straight as described above, or may be dashed (also called dotted or perforated). At least one of the incisions 41, 401, the one-side creases 42, 402, and the other-side creases 43, 403 may be dashed. This is also set depending on, for example, the strength of the cardboard and the shape after bending.

[0048] Furthermore, the thicknesses of the layers 51, 52, and 53 of the laminated cardboard sheet 1 may differ from one another. However, a laminated cardboard sheet (reinforced cardboard) formed from multiple layers of the same thickness is relatively stronger, and the folds 4 and 40 of this embodiment function more effectively. The folds 4 and 40 of this embodiment are particularly suited to reinforced cardboard. The laminated cardboard sheet 1 may be composed of two or more layers.

[0049] Furthermore, the incision 41 and the lines 42, 43 need only extend parallel to one another and do not have to be parallel. The predetermined direction in which the fold 4 extends may be a direction other than the horizontal direction (for example, the vertical direction). However, the configuration of this embodiment is particularly effective for folds that extend in the horizontal direction, which requires a high bending force during bending.

[0050] Furthermore, for example, the laminated cardboard sheet 1 may have one or more folds 4 and / or one or more folds 40. The shape of the cuts or creases in the cross section perpendicular to the folds may be V-shaped or U-shaped.

[0051] (Laminated cardboard sheet with multiple folds) As shown in FIG. 8 , the laminated cardboard sheet 1 may have multiple creases 4, 40. By folding the laminated cardboard sheet 1 along each crease 4, 40, the laminated cardboard sheet 1 can be formed into an overall arc-shaped (strictly speaking, polygonal) shape, as shown in FIG. 9 . In this way, multiple creases 4, 40 may be formed at predetermined intervals in the surface liner 21 so that the entire laminated cardboard sheet 1 becomes arc-shaped through the folding process. This folding process eliminates the need for large bending forces or specialized tools, significantly reducing the workload. For laminated cardboard sheets 1 with multiple creases 4, 40 closely spaced to bend into an arc, it is preferable that each crease 4, 40 extend vertically, from the perspective of ease of operation. A laminated cardboard sheet 1 folded into an arc can also be used, for example, as the back of a chair or the roof of a shed. When the laminated cardboard sheet 1 is folded at a right angle along one of the creases 4, 40, it becomes as shown in FIG. 10 .

[0052] As described above, the laminated cardboard sheet 1 has one or more folds 4 and / or one or more folds 40. Thus, the direction, length, depth, position, number, etc. of the folds 4, 40 are not limited to those described above. Furthermore, the number, length, shape, depth, etc. of the cuts and creases are not limited to those described above. Furthermore, the number of layers of the laminated cardboard sheet 1, the thickness of each layer, the planar shape (e.g., rectangular, square, circular), etc. are not limited to those described above. Known materials can be used for the laminated cardboard sheet 1.

[0053] (summary) The laminated cardboard sheet 1 is a laminated cardboard sheet including three or more liners 21-24, two or more corrugations 31-33, and a fold line formed in the surface liner 21 and extending in a predetermined direction. The fold line 4 has a notch 41 and a one-side crease 42. The notch 41 is formed by cutting at least the surface liner 21 so as to extend in the predetermined direction. The one-side crease 42 is formed by pressing the surface liner 21 to one side of the notch 41, and extends parallel to the notch 41 so as to partially overlap the notch 41. The notch 41 is formed deeper than the one-side crease 42. In a cross section perpendicular to the fold line, which is a cross section of the fold line 4 cut by an imaginary plane perpendicular to an imaginary line extending in the predetermined direction, the angle θ1 formed by the notch 41 and the one-side crease 42 on the back side is less than 90 degrees. Such a laminated cardboard sheet 1 may be formed, for example, as shown in Figures 12 and 13. 12 and 13, the layer structure is not shown.

[0054] The fold 40 includes a recess 40a, one or more cuts 401, and one or more creases 402, 403. The recess 40a is formed in the surface liner 21 and extends in a predetermined direction. The cut 401 is formed to extend in a predetermined direction within the recess 40a. The creases 402, 403 are formed to extend parallel to the cut 401 within the recess 40a. The cut 401 is formed deeper than the creases 402, 403 by cutting the surface liner 21. The creases 402, 403 are formed deeper than the recess 40a by pressing the surface liner 21. Note that dependent claims that depend from the same claim may depend on each other as long as they are not technically inconsistent.

[0055] As an example, a method for manufacturing a laminated cardboard sheet 1 may use a crease forming device 9, as shown in FIG. 11 , including a blade unit 91 for forming incisions, a press unit 92 for forming creases, a drive unit 93 for driving them according to a predetermined program, and wide portions 9a formed at the bases of the blade unit 91 and the press unit 92. The base ends of the blade unit 91 and the press unit 92 each have a wide portion 9a that is thicker (wider) than the blade unit 91 and the press unit 92. For example, the manufacturing of a laminated cardboard sheet 1 of the second embodiment may include a cut forming step for forming an incision 401 with the blade unit 91 and a creasing step for forming creasing lines 402 and 403 with the press unit 92. In the creasing step, the wide portion 9a presses the surface liner 21 to form recesses 40a. In this way, the recesses 40a may be composed of multiple long grooves formed by the wide portions 9a. The order of the steps may be set arbitrarily (including simultaneous steps). The crease forming device 9 can also be used to produce the crease 4. The crease 4 is formed, for example, through a plurality of steps. The crease 4, 40 in this embodiment is formed so as to be uniform in the stretching direction (predetermined direction), for example, as shown in FIG. [Explanation of symbols]

[0056] 1...laminated cardboard sheet, 21 to 24...liner, 31 to 33...core, 4, 40...fold, 41, 401...notch, 42, 402...crease on one side, 43, 403...crease on the other side, 46...sub-crease on one side, 47...sub-crease on the other side.

Claims

1. A laminated cardboard sheet including three or more liners, two or more cores, and folds extending in a predetermined direction formed on the surface of the liner, The crease is a notch extending in the predetermined direction formed by cutting the liner on the surface; a one-side crease formed by pressing the liner on the surface to one side of the incision, the one-side crease extending parallel to the incision so as to partially overlap the incision; Equipped with The incision is formed deeper than the one-side score line, In a fold perpendicular cross section, which is a cross section obtained by cutting the fold along a virtual plane perpendicular to the virtual line extending in the predetermined direction, The angle formed by the incision and the one-side ruled line on the back surface side is less than 90 degrees. Laminated corrugated cardboard sheets.

2. The fold further includes an other-side crease formed by pressing the liner on the surface on the other side of the cut, The cut is formed deeper than the other side score line, the other-side crease extends parallel to the incision so as to partially overlap the incision, In the cross section perpendicular to the fold, The angle formed by the incision and the other-side ruled line on the back surface side is less than 90 degrees. The laminated corrugated cardboard sheet according to claim 1.

3. the one-side crease and the other-side crease are formed symmetrically around the incision; The laminated corrugated cardboard sheet according to claim 2.

4. The crease is one or more one-side sub-ruled lines extending parallel to the one-side ruled line on one side of the one-side ruled line so as to partially overlap an adjacent ruled line; one or more other-side sub-ruled lines extending parallel to the other-side ruled line on the other side of the other-side ruled line so as to partially overlap an adjacent ruled line; Equipped with The laminated corrugated cardboard sheet according to claim 2.

5. The length from one end of the one-side crease to the other end of the other-side crease is greater than the length from the front surface to the back surface of the laminated cardboard sheet. The laminated corrugated cardboard sheet according to claim 2.

6. A laminated cardboard sheet consisting of three or more layers, each of said layers having the same thickness as each other; The incision is formed so as to fit into the second layer from the back surface or to reach the second layer of the liner from the back surface, the one-side crease and the other-side crease are formed so as to be contained in the first layer from the surface, The laminated corrugated cardboard sheet according to claim 2.

7. A laminated cardboard sheet including three or more liners, two or more cores, and folds extending in a predetermined direction formed on the surface of the liner, The crease is a recess formed in the liner on the surface and extending in the predetermined direction; one or more notches formed in the recess so as to extend in the predetermined direction; one or more creases formed in the recess so as to extend parallel to the notches; Equipped with The incision is formed deeper than the score line by cutting the liner on the surface, The creases are formed deeper than the recesses by pressing the liner on the surface. Laminated corrugated cardboard sheets.

8. The recess is formed of a plurality of long grooves extending in the predetermined direction and arranged in parallel so as to partially overlap each other. The laminated corrugated cardboard sheet according to claim 7.

9. The crease is a one-side crease which is the crease formed on one side of the incision; an other-side crease which is the crease formed on the other side of the incision; The laminated corrugated board sheet of claim 7, comprising:

10. The ruled lines are formed so as to partially overlap the incisions. The laminated corrugated cardboard sheet according to claim 7.

11. In a fold perpendicular cross section, which is a cross section obtained by cutting the fold along a virtual plane perpendicular to the virtual line extending in the predetermined direction, The angle between the incision and the ruled line on the back side is 120 degrees or less. The laminated corrugated cardboard sheet according to claim 10.

12. In the cross section perpendicular to the fold, The angle between the incision and the crease on the back side is less than 90 degrees. The laminated corrugated cardboard sheet according to claim 11.

13. The fold is formed symmetrically around the cut. The laminated corrugated cardboard sheet according to claim 7.

14. The crease is one or more one-side sub-ruled lines extending parallel to the one-side ruled line on one side of the one-side ruled line so as to partially overlap an adjacent one of the ruled lines; one or more other-side sub-ruled lines extending parallel to the other-side ruled line on the other side of the other-side ruled line so as to partially overlap an adjacent ruled line; Equipped with The laminated corrugated cardboard sheet according to claim 9.

15. The incision and the crease are spaced apart in the width direction, The distance between the incision and the score line is smaller than the thickness of the core. The laminated corrugated cardboard sheet according to claim 7.

16. the width of the fold is the width of the recess; The width of the recess is greater than the length from the front surface to the back surface of the laminated cardboard sheet, The laminated corrugated cardboard sheet according to claim 7.

17. A laminated cardboard sheet consisting of three or more layers, each of said layers having the same thickness as each other; The incision is formed so as to fit into the second layer from the back surface or to reach the second layer of the liner from the back surface, The ruled lines are formed so as to fit within the first layer from the surface. The laminated corrugated cardboard sheet according to claim 7.

18. A laminated cardboard sheet including three or more liners, two or more cores, and folds extending in a predetermined direction formed on the surface of the liner, The crease is a notch extending in the predetermined direction formed by cutting the liner on the surface; a one-side crease formed by pressing the liner on the surface to one side of the incision, the one-side crease extending parallel to the incision so as to partially overlap the incision; an other-side crease formed by pressing the liner on the surface to the other side of the incision, the other-side crease extending parallel to the incision so as to partially overlap the incision; Equipped with The incision is formed deeper than the one-side crease and the other-side crease, The direction along the corrugations formed by the core is defined as a vertical direction, and the direction perpendicular to the corrugations on the surface of the liner is defined as a horizontal direction. the predetermined direction is the lateral direction, In a fold perpendicular cross section, which is a cross section obtained by cutting the fold along a virtual plane perpendicular to the virtual line extending in the predetermined direction, an angle formed between the incision and the one-side crease on the back surface side, and an angle formed between the incision and the other-side crease on the back surface side, each being 120 degrees or less; Laminated corrugated cardboard sheets.

19. In the cross section perpendicular to the fold, an angle formed between the incision and the one-side crease on the back surface side, and an angle formed between the incision and the other-side crease on the back surface side, each being 90 degrees or less; The laminated corrugated cardboard sheet of claim 18.

20. The direction along the corrugations formed by the core is defined as a vertical direction, and the direction perpendicular to the corrugations on the surface of the liner is defined as a horizontal direction. the predetermined direction is the lateral direction, The laminated cardboard sheet according to any one of claims 1 to 17.

21. If the direction along the steps formed by the core is defined as the vertical direction, the predetermined direction is the vertical direction, The liner on the surface has a plurality of folds formed at predetermined intervals so that the entire laminated cardboard sheet becomes arc-shaped when folded. The laminated cardboard sheet according to any one of claims 1 to 17.

22. A manufacturing method for manufacturing the laminated cardboard sheet according to any one of claims 7 to 17, using a crease forming device comprising a blade section for forming the incisions, a pressing section for forming the creases, a driving section for driving the blade section and the creases, and wide sections formed at the bases of the blade section and the pressing section, a notch forming step of forming the notch with the blade portion; a crease forming step of forming the crease with the pressing unit; Including, At least in the crease forming step, the recess is formed by the wide portion. Manufacturing method.

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