Buffer material and packaging material

Abstract

A cushioning material and a packaging material capable of improving cushioning performance are provided. A cushioning material 100 includes sheets S11, S12, and S13, and is disposed between an object to be packaged and a packaging box for accommodating the object to be packaged. The sheets S11, S12, and S13 have a first extending portion 110 and a second extending portion 120. The first extending portion 110 has a first outer edge 111 that contacts the inner surface of the packaging box, a first inner edge 112, and an inner slit 113 extending from the first inner edge 112 in a flute direction of a corrugated cardboard sheet. The second extending portion 120 has a second outer edge 121 and an outer slit 123 extending from the second outer edge 121 in a cross direction of the corrugated cardboard sheet. In the cushioning material 100, the inner slit 113 of the sheet S11 and the outer slit 123 of the sheet S12 are engaged with each other, the inner slit 113 of the sheet S12 and the outer slit 123 of the sheet S13 are engaged with each other, and the inner slit 113 of the sheet S13 and the outer slit 123 of the sheet S11 are engaged with each other.

Description

TECHNICAL FIELD

[0001] The present invention relates to a cushioning material and a packaging material.BACKGROUND ART

[0002] Conventionally, there is known a packaging apparatus including an object to be packaged, a packaging box for storing the object to be packaged, and a cushioning material disposed between the object to be packaged and an inner wall of the packaging box to protect the object to be packaged from an external force applied to the packaging box (Patent Literature 1). The cushioning material has a configuration in which a plurality of cushioning members are assembled. The cushioning member in the assembled state can be disassembled by moving the cushioning member in a disassembly direction. At least one cushioning member constituting the cushioning material has a laminated structure in which plate-like members are laminated. Each cushioning member constituting the cushioning material contacts the object to be packaged or the inner wall of the packaging box, and movement in the disassembly direction is restricted.CITATION LISTPATENT LITERATURE

[0003] Patent Literature 1: Japanese Patent Application Publication No. 2022-016793SUMMARY OF INVENTIONTECHNICAL PROBLEM

[0004] Incidentally, a cushioning material having high cushioning performance is required.

[0005] Therefore, an object is to provide a cushioning material and a packaging material capable of improving cushioning performance.SOLUTION TO PROBLEM

[0006] A cushioning material includes a first sheet, a second sheet, and a third sheet, and is disposed between an object to be packaged and a packaging box for storing the object to be packaged.

[0007] Each of the first sheet, the second sheet, and the third sheet has a first extending portion and a second extending portion.

[0008] The second extending portion extends in a second direction perpendicular to the first direction from one end portion of the first extending portion in the first direction in which the first extending portion extends.

[0009] The first extending portion has an outer edge, an inner edge, and an inner slit.

[0010] The outer edge of the first extending portion contacts the inner surface of the packaging box.

[0011] The inner edge of the first extending portion is an inner edge opposite to the outer edge of the first extending portion, and faces the object to be packaged.

[0012] The inner slit extends in the second direction from the inner edge of the first extending portion.

[0013] The second extending portion has an outer edge and an outer slit.

[0014] The outer edge of the second extending portion faces the inner surface of the packaging box so as to be contactable with the inner surface of the packaging box.

[0015] The outer slit extends in the first direction from the outer edge of the second extending portion.

[0016] In the cushioning material, the inner slit of the first sheet and the outer slit of the second sheet are engaged with each other, the inner slit of the second sheet and the outer slit of the third sheet are engaged with each other, and the inner slit of the third sheet and the outer slit of the first sheet are engaged with each other.

[0017] Since the cushioning material is formed by engaging the first sheet, the second sheet, and the third sheet with each other, the cushioning material is less likely to be disassembled even when an impact is received from any direction. This can improve the cushioning performance.

[0018] At least one of the first sheet, the second sheet, and the third sheet may have a protruding portion that protrudes in the second direction and contacts an inner surface of the packaging box, at the outer edge of the first extending portion.

[0019] The outer edge of the first extending portion has the protruding portion that contacts the inner surface of the packaging box, and thus the strength of the cushioning material can be made appropriate. This can improve the cushioning performance.

[0020] Each of the first sheet, the second sheet, and the third sheet may have a protruding portion at the outer edge of the first extending portion.

[0021] Since each of the first sheet, the second sheet, and the third sheet has the protruding portion, the strength of the cushioning material can be made more appropriate. This can further improve the cushioning performance.

[0022] The protruding portion may have a contact surface that contacts an inner surface of the packaging box. In this case, the outer edge of the first extending portion having the protruding portion may have a flat portion that is farther from the inner surface of the packaging box than the contact surface.

[0023] Since the outer edge of the first extending portion has the flat portion that is farther from the inner surface of the packaging box than the contact surface, even if at least one of the protruding portion and the packaging box is deformed, the flat portion contacts the inner surface of the packaging box, and thus the flat portion can receive an impact. This can further improve the cushioning performance. Further deformation of the cushioning material can be suppressed.

[0024] The outer edge of the first extending portion having the protruding portion and the flat portion may have a connection portion that connects the contact surface and the flat portion and is inclined with respect to the flat portion, and the size of the protruding portion in the first direction may increase toward the flat portion in the second direction.

[0025] Since the size of the protruding portion in the first direction increases toward the flat portion in the second direction, when the protruding portion is deformed in a direction in which the protruding portion is crushed, a portion of the protruding portion that receives an impact can be gradually increased. This can suppress a decrease in the cushioning performance.

[0026] At least one of the first sheet, the second sheet, and the third sheet may have a recessed portion at a position facing a corner portion formed between two inner surfaces of the packaging box, the recessed portion having a shape recessed in a direction away from the corner portion of the packaging box.

[0027] The sheet has the recessed portion having a shape recessed in a direction away from the corner portion of the packaging box at a position facing the corner portion of the packaging box, and thus a gap can be formed between the corner portion of the packaging box and the sheet. Accordingly, even when the corner portion of the packaging box is crushed, a force is less likely to be applied to the object to be packaged via the sheet.

[0028] The second extending portion may have an inner edge opposite to the outer edge of the second extending portion and facing the object to be packaged, the inner edge of the first extending portion may be flat, and the inner edge of the second extending portion may be flat.

[0029] The inner edge facing the object to be packaged is flat, which can suppress an unnecessary force from being applied to the object to be packaged from the inner edge.

[0030] The cushioning material may have an opening capable of receiving a corner portion of the object to be packaged.

[0031] Since the cushioning material has the opening capable of receiving the corner portion of the object to be packaged, contact between the cushioning material and the corner portion of the object to be packaged can be suppressed.

[0032] The first sheet, the second sheet, and the third sheet may have the same shape.

[0033] Since the first sheet, the second sheet, and the third sheet have the same shape, the number of types of parts constituting the cushioning material can be reduced.

[0034] The first sheet, the second sheet, and the third sheet may be corrugated cardboard sheet, the first direction may be a cross direction of the corrugated cardboard sheet, and the second direction may be a flute direction of the corrugated cardboard sheet.

[0035] Since the second direction is the flute direction of the corrugated cardboard sheet, the strength of each sheet in the second direction can be increased. Thus, the cushioning material formed by assembling the plurality of sheets can firmly receive an impact even when the impact is received from any direction.

[0036] The cushioning material includes a first sheet, a second sheet, a third sheet, a fourth sheet, and a fifth sheet, and is disposed between an object to be packaged and a packaging box for storing the object to be packaged.

[0037] Each of the first sheet, the second sheet, the third sheet, and the fourth sheet has a first extending portion and a second extending portion.

[0038] The second extending portion extends in a second direction perpendicular to a first direction from one end portion of the first extending portion in the first direction in which the first extending portion extends.

[0039] The first extending portion has an outer edge, an inner edge, and an inner slit.

[0040] The outer edge of the first extending portion contacts an inner surface of the packaging box.

[0041] The inner edge of the first extending portion is an inner edge opposite to the outer edge of the first extending portion, and faces the object to be packaged.

[0042] The inner slit extends in the second direction from the inner edge of the first extending portion.

[0043] The second extending portion has an outer edge and an outer slit.

[0044] The outer edge of the second extending portion faces the inner surface of the packaging box so as to be contactable with the inner surface of the packaging box.

[0045] The outer slit extends in the first direction from the outer edge of the second extending portion.

[0046] The fifth sheet has a third extending portion, a fourth extending portion, and a fifth extending portion.

[0047] The third extending portion extends in the first direction.

[0048] The fourth extending portion extends in the second direction from one end portion of the third extending portion in the first direction.

[0049] The fifth extending portion extends in the second direction from the other end portion of the third extending portion in the first direction.

[0050] The third extending portion has an outer edge, an inner edge, a first inner slit, and a second inner slit.

[0051] The outer edge of the third extending portion contacts the inner surface of the packaging box.

[0052] The inner edge of the third extending portion is an inner edge opposite to the outer edge of the third extending portion, and faces the object to be packaged.

[0053] The first inner slit extends in the second direction from an end portion of an inner edge of the third extending portion, the end portion being closer to the fourth extending portion.

[0054] The second inner slit extends in the second direction from an end portion of an inner edge of the third extending portion, the end portion being closer to the fifth extending portion.

[0055] The fourth extending portion has an outer edge and a first outer slit.

[0056] The outer edge of the fourth extending portion faces the inner surface of the packaging box so as to be contactable with the inner surface of the packaging box.

[0057] The first outer slit extends in the first direction from the outer edge of the fourth extending portion.

[0058] The fifth extending portion has an outer edge and a second outer slit.

[0059] The outer edge of the fifth extending portion faces the inner surface of the packaging box so as to be contactable with the inner surface of the packaging box.

[0060] The second outer slit extends in the first direction from the outer edge of the fifth extending portion.

[0061] In the cushioning material, the inner slit of the first sheet and the first outer slit of the fifth sheet are engaged with each other, the first inner slit of the fifth sheet and the outer slit of the third sheet are engaged with each other, and the inner slit of the third sheet and the outer slit of the first sheet are engaged with each other.

[0062] In the cushioning material, the inner slit of the second sheet and the second outer slit of the fifth sheet are engaged with each other, the second inner slit of the fifth sheet and the outer slit of the fourth sheet are engaged with each other, and the inner slit of the fourth sheet and the outer slit of the second sheet are engaged with each other.

[0063] Since the cushioning material is formed by engaging the first sheet, the second sheet, the third sheet, the fourth sheet, and the fifth sheet with each other, the cushioning material is less likely to be disassembled even when an impact is received from any direction. This can improve the cushioning performance.

[0064] The first sheet and the second sheet may have the same shape, and the third sheet and the fourth sheet may have the same shape.

[0065] Since the first sheet and the second sheet have the same shape and the third sheet and the fourth sheet have the same shape, the number of types of parts constituting the cushioning material can be reduced.

[0066] The first sheet, the second sheet, the third sheet, the fourth sheet, and the fifth sheet may be corrugated cardboard sheets, the first direction may be a cross direction of the corrugated cardboard sheets, and the second direction may be a flute direction of the corrugated cardboard sheets.

[0067] Since the second direction is the flute direction of the corrugated cardboard sheets, the strength of each sheet in the second direction can be increased. Thus, the cushioning material formed by assembling the plurality of sheets can firmly receive an impact even when the impact is received from any direction.

[0068] The cushioning material includes a first sheet, a second sheet, a third sheet, a fourth sheet, a fifth sheet, a sixth sheet, a seventh sheet, and an eighth sheet, and is disposed between the object to be packaged and a packaging box that accommodates the object to be packaged.

[0069] Each of the first sheet, the second sheet, the third sheet, and the fourth sheet has a first extending portion and a second extending portion.

[0070] The second extending portion extends in a second direction perpendicular to a first direction from one end portion of the first extending portion in the first direction in which the first extending portion extends.

[0071] The first extending portion has an outer edge, an inner edge, and an inner slit.

[0072] The outer edge of the first extending portion contacts an inner surface of the packaging box.

[0073] The inner edge of the first extending portion is the inner edge opposite to the outer edge of the first extending portion, and faces the object to be packaged.

[0074] The inner slit extends in the second direction from an inner edge of the first extending portion.

[0075] The second extending portion has an outer edge and an outer slit.

[0076] The outer edge of the second extending portion faces the inner surface of the packaging box so as to be contactable with the inner surface of the packaging box.

[0077] The outer slit extends in the first direction from the outer edge of the second extending portion.

[0078] Each of the fifth sheet and the sixth sheet has a third extending portion, a fourth extending portion, and a fifth extending portion.

[0079] The third extending portion extends in the first direction.

[0080] The fourth extending portion extends in the second direction from one end portion of the third extending portion in the first direction.

[0081] The fifth extending portion extends in the second direction from the other end portion of the third extending portion in the first direction.

[0082] The third extending portion has an outer edge, an inner edge, a first inner slit, and a second inner slit.

[0083] The outer edge of the third extending portion contacts the inner surface of the packaging box.

[0084] The inner edge of the third extending portion is an inner edge opposite to the outer edge of the third extending portion, and faces the object to be packaged.

[0085] The first inner slit of the third extending portion extends in the second direction from an end portion of the inner edge of the third extending portion, the end portion being closer to the fourth extending portion.

[0086] The second inner slit of the third extending portion extends in the second direction from an end portion of the inner edge of the third extending portion, the end portion being closer to the fifth extending portion.

[0087] The fourth extending portion has an outer edge and a first outer slit.

[0088] The outer edge of the fourth extending portion faces the inner surface of the packaging box so as to be contactable with the inner surface of the packaging box.

[0089] The first outer slit extends in the first direction from the outer edge of the fourth extending portion.

[0090] The fifth extending portion has an outer edge and a second outer slit.

[0091] The outer edge of the fifth extending portion faces the inner surface of the packaging box so as to be contactable with the inner surface of the packaging box.

[0092] The second outer slit extends in the first direction from the outer edge of the fifth extending portion.

[0093] Each of the seventh sheet and the eighth sheet has a sixth extending portion, a seventh extending portion, and an eighth extending portion.

[0094] The sixth extending portion extends in the first direction.

[0095] The seventh extending portion extends in the first direction.

[0096] The eighth extending portion extends in the second direction and connects one end portion of the sixth extending portion and one end portion of the seventh extending portion in the first direction.

[0097] The sixth extending portion has an outer edge, an inner edge, and a first inner slit.

[0098] The outer edge of the sixth extending portion contacts the inner surface of the packaging box.

[0099] The inner edge of the sixth extending portion is an inner edge opposite to the outer edge of the sixth extending portion, and faces the object to be packaged.

[0100] The first inner slit of the sixth extending portion extends in the second direction from the inner edge of the sixth extending portion.

[0101] The seventh extending portion has an outer edge, an inner edge, and a second inner slit.

[0102] The outer edge of the seventh extending portion contacts the inner surface of the packaging box.

[0103] The inner edge of the seventh extending portion is an inner edge opposite to the outer edge of the seventh extending portion, and faces the object to be packaged.

[0104] The second inner slit of the seventh extending portion extends in the second direction from the inner edge of the seventh extending portion.

[0105] The eighth extending portion has an outer edge, a first outer slit, and a second outer slit.

[0106] The outer edge of the eighth extending portion contacts the inner surface of the packaging box.

[0107] The first outer slit extends in the first direction from an end portion of the outer edge of the eighth extending portion, the end portion being closer to the sixth extending portion.

[0108] The second outer slit extends in the first direction from an end portion of the outer edge of the eighth extending portion, the end portion being closer to the seventh extending portion.

[0109] In the packaging material, the inner slit of the first sheet and the first outer slit of the fifth sheet are engaged with each other, the first inner slit of the fifth sheet and the first outer slit of the seventh sheet are engaged with each other, and the first inner slit of the seventh sheet and the outer slit of the first sheet are engaged with each other.

[0110] In the packaging material, the inner slit of the second sheet and the second outer slit of the fifth sheet are engaged with each other, the second inner slit of the fifth sheet and the first outer slit of the eighth sheet are engaged with each other, and the first inner slit of the eighth sheet and the outer slit of the second sheet are engaged with each other.

[0111] In the packaging material, the inner slit of the third sheet and the first outer slit of the sixth sheet are engaged with each other, the first inner slit of the sixth sheet and the second outer slit of the seventh sheet are engaged with each other, and the second inner slit of the seventh sheet and the outer slit of the third sheet are engaged with each other.

[0112] In the packaging material, the inner slit of the fourth sheet and the second outer slit of the sixth sheet are engaged with each other, the second inner slit of the sixth sheet and the second outer slit of the eighth sheet are engaged with each other, and the second inner slit of the eighth sheet and the outer slit of the fourth sheet are engaged with each other.

[0113] Since the cushioning material is formed by engaging the first sheet, the second sheet, the third sheet, the fourth sheet, the fifth sheet, the sixth sheet, the seventh sheet, and the eighth sheet with each other, the cushioning material is less likely to be disassembled even when an impact is received from any direction. This can improve the cushioning performance.

[0114] The first sheet, the second sheet, the third sheet, and the fourth sheet may have the same shape, the fifth sheet and the sixth sheet may have the same shape, and the seventh sheet and the eighth sheet may have the same shape.

[0115] Since the first sheet, the second sheet, the third sheet, and the fourth sheet have the same shape, the fifth sheet and the sixth sheet have the same shape, and the seventh sheet and the eighth sheet have the same shape, the number of types of parts constituting the cushioning material can be reduced.

[0116] The first sheet, the second sheet, the third sheet, the fourth sheet, the fifth sheet, the sixth sheet, the seventh sheet, and the eighth sheet may be corrugated cardboard sheets, the first direction may be a cross direction of the corrugated cardboard sheets, and the second direction may be a flute direction of the corrugated cardboard sheets.

[0117] Since the second direction is the flute direction of the corrugated cardboard sheet, the strength of each sheet in the second direction can be increased. Thus, the cushioning material formed by assembling the plurality of sheets can firmly receive an impact even when the impact is received from any direction.

[0118] The packaging material includes the cushioning material and an intermediate sheet disposed between the cushioning material and the object to be packaged.

[0119] Since the packaging material includes the intermediate sheet disposed between the cushioning material and the object to be packaged, the cushioning material and the object to be packaged do not directly contact each other. This can improve the cushioning performance.

[0120] The fourth edge The dimension from the outer edge to the inner edge of the first sheet may be greater than or equal to the sum of the length of the inner slit and the length of the outer slit.

[0121] Since the dimension from the fourth edge to the first contact surface is greater than or equal to the sum of the length of the first slit and the length of the second slit, the first edge reliably contacts the first inner surface of the packaging box.

[0122] The cushioning material includes a plurality of sheets, is a cushioning material formed by assembling the plurality of sheets, is disposed between the object to be packaged and a packaging box for storing the object to be packaged, and contacts at least a first inner surface of the packaging box and a second inner surface of the packaging box adjacent to the first inner surface.

[0123] The plurality of sheets includes a first corrugated cardboard sheet.

[0124] The first corrugated cardboard sheet has a first edge facing the first inner surface of the packaging box.

[0125] The first edge has a first protruding portion that protrudes toward the first inner surface of the packaging box and contacts the first inner surface of the packaging box.

[0126] Since the first edge of the first corrugated cardboard sheet has the first protruding portion that contacts the first inner surface of the packaging box, the strength of the cushioning material can be made appropriate. Since the cushioning material contacts the first inner surface and the second inner surface of the packaging box, an impact can be received from two directions. This can improve the cushioning performance.

[0127] The first protruding portion may have a first contact surface that contacts the first inner surface of the packaging box, and the first edge may have a flat portion that is farther from the first inner surface of the packaging box than the first contact surface.

[0128] Since the first edge has the flat portion that is farther from the first inner surface of the packaging box than the first contact surface, even when at least one of the first protruding portion and the packaging box is deformed, the flat portion contacts the first inner surface of the packaging box, and thus an impact can be received by the flat portion. This can further improve the cushioning performance. Further deformation of the cushioning material can be suppressed.

[0129] The first edge may have a connection portion that connects the first contact surface and the flat portion and is inclined with respect to the flat portion, and a size of the first protruding portion in a direction perpendicular to a protruding direction in which the first protruding portion protrudes may increase toward the flat portion in the protruding direction.

[0130] Since the size of the first protruding portion in the direction perpendicular to the protruding direction in which the first protruding portion protrudes increases toward the flat portion in the protruding direction, when the first protruding portion is deformed in the direction in which the first protruding portion is crushed, the portion of the first protruding portion that receives the impact can be made to be gradually increased. This can suppress a decrease in the cushioning performance.

[0131] The plurality of sheets may include a second corrugated cardboard sheet, the second corrugated cardboard sheet may have a second edge facing the second inner surface of the packaging box, and the second edge may have a second protruding portion protruding toward the second inner surface of the packaging box and contacting the second inner surface of the packaging box.

[0132] Since the second edge of the second corrugated cardboard sheet has the second protruding portion that contacts the second inner surface of the packaging box, the strength of the cushioning material can be made appropriate. This can improve the cushioning performance.

[0133] The plurality of sheets may include a third corrugated cardboard sheet, the third corrugated cardboard sheet may have a third edge facing a third inner surface of the packaging box adjacent to both the first inner surface and the second inner surface, and the third edge may have a third protruding portion protruding toward the third inner surface of the packaging box and contacting the third inner surface of the packaging box.

[0134] Since the third edge of the third corrugated cardboard sheet has the third protruding portion that contacts the third inner surface of the packaging box, the strength of the cushioning material can be made appropriate. Since the cushioning material contacts the first inner surface, the second inner surface, and the third inner surface of the packaging box, an impact can be received from three directions. This can improve the cushioning performance.

[0135] The first protruding portion may protrude in the flute direction of the first corrugated cardboard sheet.

[0136] Since the first protruding portion protrudes in the flute direction of the first corrugated cardboard sheet, the impact resistance of the first protruding portion can be improved.ADVANTAGEOUS EFFECTS OF INVENTION

[0137] The cushioning performance can be improved.BRIEF DESCRIPTION OF DRAWINGS

[0138] FIG. 1 is a diagram showing a packaging material of a first embodiment. FIGS. 2A and 2B are perspective views of a cushioning material of the first embodiment. FIG. 3 is an exploded perspective view of the cushioning material of the first embodiment. FIG. 4 is a view showing a sheet constituting the cushioning material of the first embodiment. FIG. 5A is a view of the cushioning material of the first embodiment as viewed along arrow A in FIG. 2A, and FIG. 5B is a view of the cushioning material of the first embodiment as viewed along arrow B in FIG. 2A. FIG. 6 is a view of the cushioning material of the first embodiment as viewed along arrow C in FIG. 2A. FIG. 7 is a perspective view of a packaging material of a second embodiment as viewed from above. FIG. 8 is a perspective view of the packaging material of the second embodiment as viewed from below. FIGS. 9A and 9B are views showing sheets constituting a cushioning material of a second embodiment. FIG. 10 is a view showing a sheet constituting the cushioning material of the second embodiment. FIG. 11 is a top view of the packaging material of the second embodiment. FIG. 12 is a view of the packaging material of the second embodiment as viewed along arrow D in FIG. 11. FIG. 13 is a view of the packaging material of the second embodiment as viewed along arrow E in FIG. 11. FIGS. 14A and 14B are views showing sheets constituting the cushioning material of the second embodiment. FIG. 15 is a view of the packaging material of the second embodiment as viewed from below. DESCRIPTION OF EMBODIMENTS

[0139] Next, a first embodiment will be described.

[0140] As shown in FIG. 1, a packaging material 1 of the first embodiment includes a packaging box 10 and eight cushioning materials 100. The packaging box 10 is a box that accommodates an object to be packaged 20. In the embodiment, the packaging box 10 is a rectangular parallelepiped corrugated cardboard box. The packaging box 10 has six inner surfaces inside.

[0141] The type of the object to be packaged 20 is not particularly limited. The object to be packaged 20 is, for example, an electronic device, an electrical appliance, an electronic component, furniture, a machine, a mechanical component, a foodstuff, and so on. In the embodiment, the object to be packaged 20 has an appearance of a substantially rectangular parallelepiped shape. The object to be packaged 20 has eight corner portions 21. As an example, the object to be packaged 20 is a printer as an electronic device.

[0142] The cushioning material 100 is disposed between the object to be packaged 20 and the packaging box 10. Specifically, the cushioning material 100 is disposed between the object to be packaged 20 and the packaging box 10 so as to engage with the corner portions 21 of the object to be packaged 20.

[0143] As shown in FIGS. 2A, 2B and 3, the cushioning material 100 includes a plurality of sheets S11, S12, and S13, and is formed by assembling the plurality of sheets S11, S12, and S13. Specifically, the plurality of sheets S11, S12, and S13 include a first sheet S11, a second sheet S12, and a third sheet S13. In other words, the cushioning material 100 includes the first sheet S11, the second sheet S12, and the third sheet S13.

[0144] The first sheet S11, the second sheet S12, and the third sheet S13 are formed of corrugated cardboard sheets. The "corrugated cardboard sheet" may be, for example, a corrugated cardboard sheet having one flute of the medium or a corrugated cardboard sheet having a plurality of flutes of the medium. The "corrugated cardboard sheet" may be, for example, a plurality of corrugated cardboard sheets bonded to each other.

[0145] In the embodiment, the "first direction" is a cross direction of the corrugated cardboard sheet, and hereinafter, is also simply referred to as a "cross direction". The "second direction perpendicular to the first direction" is a flute direction of the corrugated cardboard sheet, and is hereinafter also simply referred to as a "flute direction". The cross direction is a direction perpendicular to the flutes of the corrugated cardboard sheet, and the flute direction is a direction parallel to the flutes of the corrugated cardboard sheet. The corrugated cardboard sheet has a higher strength in the flute direction than in the cross direction.

[0146] In the embodiment, the first sheet S11, the second sheet S12 and the third sheet S13 are of the same shape. The first sheet S11, the second sheet S12, and the third sheet S13 are the same size. In other words, in the cushioning material 100, the first sheet S11, the second sheet S12, and the third sheet S13 are common parts.

[0147] As shown in FIG. 4, each of the first sheet S11, the second sheet S12, and the third sheet S13 has an L-shape and has a first extending portion 110 and a second extending portion 120. The first extending portion 110 extends in the cross direction. The second extending portion 120 extends in the flute direction from one end portion of the first extending portion 110 in the cross direction in which the first extending portion 110 extends.

[0148] The first extending portion 110 has a first outer edge 111, a first inner edge 112 opposite to the first outer edge 111, and an inner slit 113. The first outer edge 111 is an outer edge of the first extending portion 110 and faces the inner surface 11 of the packaging box 10. Furthermore, the first outer edge 111 contacts an inner surface 11 of the packaging box 10. The first inner edge 112 is an inner edge of the first extending portion 110 and faces the object to be packaged 20.

[0149] The first extending portion 110 has a protruding portion 114 on the first outer edge 111. In other words, the first outer edge 111 has the protruding portion 114. The protruding portion 114 is a portion that contacts the inner surface 11 of the packaging box 10, and protrudes toward the inner surface 11 of the packaging box 10. Specifically, the protruding portion 114 protrudes in the flute direction of the corrugated cardboard sheet. The protruding portion 114 has a contact surface 115 that contacts the inner surface 11 of the packaging box 10. The contact surface 115 is substantially parallel to the cross direction.

[0150] The first outer edge 111 having the protruding portion 114 has a flat portion 116. The flat portion 116 is located at a position farther from the inner surface 11 of the packaging box 10 than the contact surface 115 of the protruding portion 114. The flat portion 116 is substantially parallel to the cross direction. The flat portion 116 is substantially parallel to the contact surface 115.

[0151] The first outer edge 111 having the protruding portion 114 and the flat portion 116 further has a connection portion 117. The connection portion 117 is a portion that connects the contact surface 115 and the flat portion 116. The connection portion 117 is inclined with respect to the flat portion 116. The connection portion 117 is inclined so as to be separated from the inner surface 11 of the packaging box 10 which the contact surface 115 contacts as the connection portion 117 is separated from the contact surface 115.

[0152] The protruding portion 114 has a trapezoidal shape. One edge of the protruding portion 114 in the cross direction is the connection portion 117. The other edge of the protruding portion 114 in the cross direction is inclined so as to be separated from the inner surface 11 of the packaging box 10 which the contact surface 115 contacts as the edge is separated from the contact surface 115, similarly to the connection portion 117.

[0153] The size of the protruding portion 114 in the cross direction increases as the distance from the inner surface 11 of the packaging box 10 which the contact surface 115 contacts increases. In other words, the size of the protruding portion 114 in the cross direction increases toward the flat portion 116 in the flute direction. In the embodiment, the flute direction corresponds to a "protruding direction in which the first protruding portion protrudes", and the cross direction corresponds to a "direction perpendicular to the protruding direction".

[0154] The first inner edge 112 is flat. The first inner edge 112 is flat except for the inner slit 113. The first inner edge 112 is substantially parallel to the cross direction. The first inner edge 112 is substantially parallel to the contact surface 115. The first inner edge 112 is substantially parallel to the flat portion 116.

[0155] The inner slit 113 extends in the flute direction from the first inner edge 112 toward the first outer edge 111. Specifically, the inner slit 113 extends in the flute direction from the first inner edge 112 toward the contact surface 115 of the first outer edge 111. In other words, the inner slit 113 is provided at a position overlapping the contact surface 115 in the cross direction.

[0156] The second extending portion 120 has a second outer edge 121, a second inner edge 122 opposite to the second outer edge 121, and an outer slit 123. The second outer edge 121 is an outer edge of the second extending portion 120 and faces the inner surface 11 of the packaging box 10. Furthermore, the second outer edge 121 faces the inner surface 11 of the packaging box 10 so as to be contactable with the inner surface 11 of the packaging box 10. The second inner edge 122 is an inner edge of the second extending portion 120 and faces the object to be packaged 20.

[0157] The second outer edge 121 has a protruding portion 124. The protruding portion 124 is a portion capable of contacting the inner surface 11 of the packaging box 10, and protrudes toward the inner surface 11 of the packaging box 10. Specifically, the protruding portion 124 protrudes in the cross direction of the corrugated cardboard sheet. The protruding portion 124 has a contact surface 125 capable of contacting the inner surface 11 of the packaging box 10. The contact surface 125 is substantially parallel to the flute direction.

[0158] The second inner edge 122 is flat. The second inner edge 122 is substantially parallel to the flute direction. The second inner edge 122 is substantially parallel to the contact surface 125.

[0159] The outer slit 123 extends in the cross direction from the second outer edge 121 toward the second inner edge 122. Specifically, the outer slit 123 extends in the cross direction from the contact surface 125 toward the second inner edge 122.

[0160] A dimension D1 from the first inner edge 112 to the contact surface 115 is greater than or equal to the sum of a length L1 of the inner slit 113 and a length L2 of the outer slit 123. In the embodiment, the dimension D1 from the first inner edge 112 to the contact surface 115 is equal to the sum of the length L1 of the inner slit 113 and the length L2 of the outer slit 123.

[0161] Each of the first sheet S11, the second sheet S12, and the third sheet S13 has a recessed portion 141. The recessed portion 141 is provided at a position facing a corner portion 12 formed between the two inner surfaces 11, 11 of the packaging box 10. Specifically, the recessed portion 141 is provided at a position corresponding to the corner portion of the L-shape of each of the sheets S11, S12, and S13. The recessed portion 141 has a shape recessed in a direction away from the corner portion 12 of the packaging box 10 from the corner portion 12 of the packaging box 10 toward the object to be packaged 20.

[0162] As shown in FIG. 3, the cushioning material 100 is assembled by engaging the inner slit 113 of the first sheet S11 with the outer slit 123 of the second sheet S12, engaging the inner slit 113 of the second sheet S12 with the outer slit 123 of the third sheet S13, and engaging the inner slit 113 of the third sheet S13 with the outer slit 123 of the first sheet S11.

[0163] As shown in FIGS. 2A and 2B, the cushioning material 100 has an opening 151 in an assembled state. The opening 151 is formed by the first inner edges 112 and the second inner edges 122 of the three sheets S11, S12, S13. As shown in FIG. 1, the opening 151 is capable of receiving the corner portion 21 of the object to be packaged 20.

[0164] As shown in FIGS. 5A, 5B and 6, the cushioning material 100 contacts three inner surfaces 11 of the packaging box 10. Specifically, the cushioning material 100 contacts an inner surface 11A, an inner surface 11B adjacent to the inner surface 11A, and an inner surface 11C adjacent to both the inner surfaces 11A and 11B of the packaging box 10.

[0165] As shown in FIG. 5A, the contact surface 115 of the first sheet S11 of the cushioning material 100 contacts the inner surface 11A of the packaging box 10, and the contact surface 125 contacts the inner surface 11C of the packaging box 10. As shown in FIG. 5B, the contact surface 115 of the second sheet S12 of the cushioning material 100 contacts the inner surface 11B of the packaging box 10, and the contact surface 125 contacts the inner surface 11A of the packaging box 10. As shown in FIG. 6, the contact surface 115 of the third sheet S13 of the cushioning material 100 contacts the inner surface 11C of the packaging box 10, and the contact surface 125 contacts the inner surface 11B of the packaging box 10.

[0166] In the cushioning material 100, one of the first sheet S11, the second sheet S12, and the third sheet S13 corresponds to a "first corrugated cardboard sheet". The first outer edge 111 of the sheet corresponding to the first corrugated cardboard sheet corresponds to a "first edge", the protruding portion 114 corresponds to a "first protruding portion", the contact surface 115 corresponds to a "first contact surface", the first inner edge 112 corresponds to a "fourth edge", and the inner slit 113 corresponds to a "first slit". The inner surface 11 of the packaging box 10 facing the first outer edge 111 of the sheet corresponding to the first corrugated cardboard sheet corresponds to a "first inner surface".

[0167] A sheet having the outer slit 123 that engages with the inner slit 113 of the sheet corresponding to the first corrugated cardboard sheet corresponds to a "second corrugated cardboard sheet". The first outer edge 111 of the sheet corresponding to the second corrugated cardboard sheet corresponds to a "second edge", the protruding portion 114 corresponds to a "second protruding portion", the second outer edge 121 corresponds to a "fifth edge", the protruding portion 124 corresponds to a "fourth protruding portion", the contact surface 125 corresponds to a "second contact surface", the second inner edge 122 corresponds to a "sixth edge", and the outer slit 123 corresponds to a "second slit". The inner surface 11 of the packaging box 10 facing the first outer edge 111 of the sheet corresponding to the second corrugated cardboard sheet corresponds to a "second inner surface adjacent to the first inner surface".

[0168] A sheet having the outer slit 123 that engages with the inner slit 113 of the sheet corresponding to the second corrugated cardboard sheet corresponds to a "third corrugated cardboard sheet". The first outer edge 111 of the sheet corresponding to the third corrugated cardboard sheet corresponds to a "third edge", and the protruding portion 114 corresponds to a "third protruding portion". The inner surface 11 of the packaging box 10 facing the first outer edge 111 of the sheet corresponding to the third corrugated cardboard sheet corresponds to a "third inner surface adjacent to both the first inner surface and the second inner surface".

[0169] Next, the effect of the cushioning material 100 will be described.

[0170] Since the cushioning material 100 is formed by engaging the first sheet S11, the second sheet S12, and the third sheet S13 with each other, the cushioning material 100 is less likely to be disassembled even when an impact is received from any direction. This can improve the cushioning performance.

[0171] Since the inner slit 113 of the first sheet S11 and the outer slit 123 of the second sheet S12 are engaged with each other, the first sheet S11 and the second sheet S12 can be in a state of crossing each other. Since the inner slit 113 of the second sheet S12 and the outer slit 123 of the third sheet S13 are engaged with each other, the second sheet S12 and the third sheet S13 can be in a state of crossing each other. Since the inner slit 113 of the third sheet S13 and the outer slit 123 of the first sheet S11 are engaged with each other, the third sheet S13 and the first sheet S11 can be in a state of crossing each other. This can improve the impact resistance.

[0172] Since the first outer edge 111 has the protruding portion 114 that contacts the inner surface 11 of the packaging box 10, the strength of the cushioning material 100 can be made appropriate as compared with a case where the entire outer edge of the first extending portion contacts the inner surface 11 of the packaging box 10. This can improve the cushioning performance.

[0173] In the embodiment, since each of the first sheet S11, the second sheet S12, and the third sheet S13 has the protruding portion 114, the strength of the cushioning material 100 can be made more appropriate. This can further improve the cushioning performance.

[0174] Since the cushioning material 100 contacts the inner surfaces 11A and 11B of the packaging box 10, an impact can be received from two directions. Since the cushioning material 100 contacts the inner surfaces 11A, 11B, and 11C of the packaging box 10, an impact can be received from three directions. This can improve the cushioning performance.

[0175] Since the first outer edge 111 has the flat portion 116 that is farther from the inner surface 11 of the packaging box 10 than the contact surface 115, even if at least one of the protruding portion 114 and the packaging box 10 is deformed, the flat portion 116 contacts the inner surface 11 of the packaging box 10, and thus the flat portion 116 can receive an impact. This can further improve the cushioning performance. Further deformation of the cushioning material 100 can be suppressed.

[0176] Since the size of the protruding portion 114 in the cross direction increases toward the flat portion 116 in the flute direction, when the protruding portion 114 is deformed in the crushing direction, the portion of the protruding portion 114 that receives an impact can be gradually increased. This can suppress a decrease in the cushioning performance.

[0177] Since the inner slit 113 extends from the first inner edge 112 toward the first outer edge 111, the first outer edge 111 that contacts the inner surface 11 of the packaging box 10 is not divided by the slit, and thus the strength of the first outer edge 111 is not reduced.

[0178] Since the inner slit 113 extends from the first inner edge 112 toward the contact surface 115, the contact surface 115 that contacts the inner surface 11 of the packaging box 10 is not divided by the slit, and thus the strength of the contact surface 115 is not reduced.

[0179] Since the dimension D1 from the first inner edge 112 to the contact surface 115 is equal to the sum of the length L1 of the inner slit 113 and the length L2 of the outer slit 123, the first outer edge 111 and the second outer edge 121 are flush with each other when the inner slit 113 and the outer slit 123 are engaged with each other. In other words, the second outer edge 121 does not protrude toward the inner surface 11 of the packaging box 10 from the first outer edge 111. This ensures that the first outer edge 111 contacts the inner surface 11 of the packaging box 10.

[0180] Furthermore, when the inner slit 113 and the outer slit 123 are engaged with each other, the contact surface 115 and the contact surface 125 are flush with each other. In other words, the contact surface 125 does not protrude toward the inner surface 11 of the packaging box 10 from the contact surface 115. This ensures that the contact surface 115 contacts the inner surface 11 of the packaging box 10.

[0181] The first inner edge 112 facing the object to be packaged 20 is flat, which can suppress an unnecessary force from being applied to the object to be packaged 20 from the first inner edge 112.

[0182] The second inner edge 122 facing the object to be packaged 20 is flat, which can suppress an unnecessary force from being applied to the object to be packaged 20 from the second inner edge 122.

[0183] Since the cushioning material 100 has the opening 151 capable of receiving the corner portion 21 of the object to be packaged 20, contact between the cushioning material 100 and the corner portion 21 of the object to be packaged 20 can be suppressed.

[0184] Since the protruding portion 114 protrudes in the flute direction of the corrugated cardboard sheet, the impact resistance of the protruding portion 114 can be improved.

[0185] Since the "second direction" is the flute direction of the corrugated cardboard sheet, the strength of each of the sheets S11, S12, and S13 in the "second direction" can be increased. Thus, the cushioning material 100 formed by assembling the plurality of sheets S11, S12, and S13 can firmly receive an impact even when the impact is received from any direction.

[0186] Since the sheets S11, S12, and S13 have the recessed portion 141 recessed in a direction away from the corner portion 12 of the packaging box 10 at a position facing the corner portion 12 of the packaging box 10, a gap can be formed between the corner portion 12 of the packaging box 10 and the sheets S11, S12, and S13. Thus, even if the corner portion of the packaging box 10 is crushed, a force is less likely to be applied to the object to be packaged 20 through the sheets S11, S12, and S13.

[0187] Since the first sheet S11, the second sheet S12, and the third sheet S13 have the same shape, the number of types of parts constituting the cushioning material 100 can be reduced.

[0188] Next, a second embodiment will be described. In the following, the description will be made focusing on the points different from the embodiment described above. In each sheet, portions having the same function are denoted by the same reference numerals even if the shapes are different, and the description thereof will be omitted.

[0189] As shown in FIGS. 7 and 8, a packaging material 2 of the second embodiment includes the packaging box 10, a cushioning material 200, and an intermediate sheet 300. The cushioning material 200 includes two first cushioning materials 201 and a second cushioning material 202. The intermediate sheet 300 includes a first intermediate sheet 310 and a second intermediate sheet 320. In the embodiment, the two first cushioning materials 201 and the first intermediate sheet 310 are disposed in an upper portion of the packaging box 10, and the second cushioning material 202 and the second intermediate sheet 320 are disposed in a lower portion of the packaging box 10.

[0190] As shown in FIG. 7, each of the first cushioning materials 201 includes a first sheet S21, a second sheet S22, a third sheet S23, a fourth sheet S24, and a fifth sheet S25. The first sheet S21, the second sheet S22, the third sheet S23, the fourth sheet S24, and the fifth sheet S25 are formed of corrugated cardboard sheets.

[0191] In the embodiment, the first sheet S21 and the second sheet S22 have the same shape. The first sheet S21 and the second sheet S22 have the same size. In other words, the first sheet S21 and the second sheet S22 of the first cushioning material 201 are common parts. The third sheet S23 and the fourth sheet S24 have the same shape. The third sheet S23 and the fourth sheet S24 have the same size. In other words, in the first cushioning material 201, the third sheet S23 and the fourth sheet S24 are common parts.

[0192] As shown in FIGS. 9A and 9B, each of the first sheet S21, the second sheet S22, the third sheet S23, and the fourth sheet S24 has a first extending portion 110 and a second extending portion 120. The first extending portion 110 has a first outer edge 111, a first inner edge 112, and an inner slit 113. The first extending portion 110 has a protruding portion 114 on the first outer edge 111, and the protruding portion 114 has a contact surface 115. The second extending portion 120 has a second outer edge 121, a second inner edge 122, and an outer slit 123. The second outer edge 121 has a protruding portion 124, and the protruding portion 124 has a contact surface 125.

[0193] As shown in FIG. 9A, each of the first sheet S21 and the second sheet S22 has a reinforcement portion 142. The reinforcement portion 142 is provided at a position facing the corner portion 12 of the packaging box 10. Specifically, the reinforcement portions 142 is provided at a position corresponding to the corner portion of the L-shape of each of the sheet S21 and the sheet S22. The reinforcement portion 142 contacts two adjacent inner surfaces 11, 11 forming the corner portion 12 of the packaging box 10.

[0194] As shown in FIG. 10, the fifth sheet S25 has a U-shape, and has a third extending portion 230, a fourth extending portion 240, and a fifth extending portion 250. The third extending portion 230 extends in the cross direction. The fourth extending portion 240 extends in the flute direction from one end portion of the third extending portion 230 in the cross direction. The fifth extending portion 250 extends in the flute direction from the other end portion of the third extending portion 230 in the cross direction.

[0195] The third extending portion 230 has a third outer edge 231, a third inner edge 232 opposite to the third outer edge 231, a first inner slit 233A, and a second inner slit 233B. The third outer edge 231 is an outer edge of the third extending portion 230 and contacts the inner surface 11 of the packaging box 10. The third inner edge 232 is an inner edge of the third extending portion 230 and faces the object to be packaged 20.

[0196] The third extending portion 230 has protruding portions 234A and 234B on the third outer edge 231. The protruding portions 234A and 234B are portions that contact the inner surface 11 of the packaging box 10. The protruding portion 234A protrudes from an end portion of the third extending portion 230 in the cross direction, which is close to the fourth extending portion 240, toward the inner surface 11 of the packaging box 10. The protruding portion 234B protrudes from an end portion of the third extending portion 230 in the cross direction, which is close to the fifth extending portion 250, toward the inner surface 11 of the packaging box 10.

[0197] The protruding portions 234A and 234B protrude in the flute direction. The protruding portion 234A has a contact surface 235A that contacts the inner surface 11 of the packaging box 10. The protruding portion 234B has a contact surface 235B that contacts the inner surface 11 of the packaging box 10.

[0198] The third outer edge 231 has a flat portion 236. The flat portion 236 is located at a position separated farther from the inner surface 11 of the packaging box 10 than the contact surfaces 235A and 235B of the protruding portions 234A and 234B. The flat portion 236 is provided at three locations, namely, on one side of the protruding portion 234A in the cross direction, between the protruding portion 234A and the protruding portion 234B, and on the other side of the protruding portion 234B in the cross direction.

[0199] The protruding portions 234A and 234B have a trapezoidal shape as with the protruding portion 114. The size of the protruding portion 234A in the cross direction increases toward the flat portion 236 in the flute direction. The size of the protruding portion 234B in the cross direction increases toward the flat portion 236 in the flute direction.

[0200] The third inner edge 232 is flat. The third inner edge 232 is flat except for the inner slits 233A and 233B.

[0201] The first inner slit 233A extends in the flute direction from an end portion of the third inner edge 232 close to the fourth extending portion 240. Specifically, the first inner slit 233A extends in the flute direction from the third inner edge 232 toward the contact surface 235A of the protruding portion 234A. The second inner slit 233B extends in the flute direction from an end portion of the third inner edge 232 close to the fifth extending portion 250. Specifically, the second inner slit 233B extends in the flute direction from the third inner edge 232 toward the contact surface 235B of the protruding portion 234B.

[0202] The fourth extending portion 240 has a fourth outer edge 241, a fourth inner edge 242 opposite to the fourth outer edge 241, and a first outer slit 243. The fourth outer edge 241 is an outer edge of the fourth extending portion 240 and faces the inner surface 11 of the packaging box 10 so as to be contactable with the inner surface 11 of the packaging box 10. The fourth inner edge 242 is an inner edge of the fourth extending portion 240 and faces the object to be packaged 20. The fourth outer edge 241 and the fourth inner edge 242 are flat.

[0203] The first outer slit 243 extends in the cross direction from the fourth outer edge 241 toward the fourth inner edge 242. As shown in FIGS. 9A and 10, a dimension D2 from the first inner edge 112 of the first sheet S21 to the contact surface 115 is greater than the sum of a length L3 of the inner slit 113 and a length L4 of the first outer slit 243.

[0204] The fourth outer edge 241 of the fifth sheet S25 is separated from the inner surface 11 of the packaging box 10 in an initial state of packaging. The initial state of the packaging is a state immediately after the object to be packaged 20 is packaged with the packaging material 2, and is a state before the packaging box 10, the cushioning material 200, and so on are deformed by an impact and so on applied during transportation.

[0205] The fifth extending portion 250 has a fifth outer edge 251, a fifth inner edge 252 opposite to the fifth outer edge 251, and a second outer slit 253. The fifth outer edge 251 is an outer edge of the fifth extending portion 250 and faces the inner surface 11 of the packaging box 10 so as to be contactable with the inner surface 11 of the packaging box 10. The fifth inner edge 252 is an inner edge of the fifth extending portion 250 and faces the object to be packaged 20. The fifth outer edge 251 and the fifth inner edge 252 are flat.

[0206] The second outer slit 253 extends in the cross direction from the fifth outer edge 251 toward the fifth inner edge 252. As shown in FIGS. 9A and 10, the dimension D2 from the first inner edge 112 of the second sheet S22 to the contact surface 115 is greater than the sum of the length L3 of the inner slit 113 and the length L4 of the second outer slit 253. The fifth outer edge 251 is separated from the inner surface 11 of the packaging box 10 in the initial state of packaging.

[0207] In the embodiment, the fifth sheet S25 has a shape symmetrical with respect to the center in the cross direction.

[0208] In the first cushioning material 201, the inner slit 113 of the first sheet S21 and the first outer slit 243 of the fifth sheet S25 are engaged with each other, the first inner slit 233A of the fifth sheet S25 and the outer slit 123 of the third sheet S33 are engaged with each other, and the inner slit 113 of the third sheet S23 and the outer slit 123 of the first sheet S21 are engaged with each other. In the first cushioning material 201, the inner slit 113 of the second sheet S22 and the second outer slit 253 of the fifth sheet S25 are engaged with each other, the second inner slit 233B of the fifth sheet S25 and the outer slit 123 of the fourth sheet S24 are engaged with each other, and the inner slit 113 of the fourth sheet S24 and the outer slit 123 of the second sheet S22 are engaged with each other.

[0209] As shown in FIGS. 11 to 13, the first cushioning material 201 contacts four inner surfaces 11 of the packaging box 10. As an example, as illustrated in FIG. 11, in the first cushioning material 201, the contact surface 115 of the first sheet S21 contacts the inner surface 11A of the packaging box 10, and the contact surface 125 contacts the inner surface 11C of the packaging box 10 adjacent to the inner surface 11A. In the first cushioning material 201, the contact surface 115 of the second sheet S22 contacts an inner surface 11D of the packaging box 10 adjacent to the inner surface 11C, and the contact surface 125 contacts the inner surface 11C of the packaging box 10.

[0210] As shown in FIG. 12, in the first cushioning material 201, the contact surfaces 115 and of the third sheet S23 and the fourth sheet S24 contact the inner surface 11C of the packaging box 10, and the contact surfaces 125 contact the inner surface 11B of the packaging box 10 adjacent to the inner surfaces 11A, 11C, and 11D.

[0211] As shown in FIG. 13, in the first cushioning material 201, each of the contact surfaces 235A and 235B of the fifth sheet S25 contacts the inner surface 11B of the packaging box 10. The fourth outer edge 241 of the fifth sheet S25 does not contact the inner surface 11A of the packaging box 10. The fifth outer edge 251 of the fifth sheet S25 does not contact the inner surface 11D of the packaging box 10.

[0212] In the first cushioning material 201, the first sheet S21 corresponds to a "first corrugated cardboard sheet", for example. The first outer edge 111 of the first sheet S21 corresponds to a "first edge", the protruding portion 114 corresponds to a "first protruding portion", the contact surface 115 corresponds to a "first contact surface", the first inner edge 112 corresponds to a "fourth edge", and the inner slit 113 corresponds to a "first slit". The inner surface 11 of the packaging box 10 facing the first outer edge 111 of the first sheet S21 corresponds to a "first inner surface".

[0213] The fifth sheet S25 corresponds to a "second corrugated cardboard sheet". The third outer edge 231 of the fifth sheet S25 corresponds to a "second edge", the protruding portion 234A corresponds to a "second protruding portion", the fourth outer edge 241 corresponds to a "fifth edge", the fourth inner edge 242 corresponds to a "sixth edge", and the first outer slit 243 corresponds to a "second slit". The inner surface 11 of the packaging box 10 facing the third outer edge 231 of the fifth sheet S25 corresponds to a "second inner surface".

[0214] The third sheet S23 corresponds to a "third corrugated cardboard sheet". The first outer edge 111 of the third sheet S23 corresponds to a "third edge", and the protruding portion 114 corresponds to a "third protruding portion". The inner surface 11 of the packaging box 10 facing the first outer edge 111 of the third sheet S23 corresponds to a "third inner surface".

[0215] As shown in FIG. 8, the second cushioning material 202 includes a first sheet S31, a second sheet S32, a third sheet S33, a fourth sheet S34, a fifth sheet S35, a sixth sheet S36, a seventh sheet S37, and an eighth sheet S38. The first sheet S31, the second sheet S32, the third sheet S33, the fourth sheet S34, the fifth sheet S35, the sixth sheet S36, the seventh sheet S37, and the eighth sheet S38 are formed of corrugated cardboard sheets.

[0216] In the embodiment, the first sheet S31, the second sheet S32, the third sheet S33 and the fourth sheet S34 are of the same shape. The first sheet S31, the second sheet S32, the third sheet S33, and the fourth sheet S34 have the same size. In other words, in the second cushioning material 202, the first sheet S31, the second sheet S32, the third sheet S33, and the fourth sheet S34 are common parts.

[0217] Furthermore, the first sheet S31, the second sheet S32, the third sheet S33, and the fourth sheet S34 have the same shape as the first sheet S21 and the second sheet S22 of the first cushioning material 201. The first sheet S31, the second sheet S32, the third sheet S33, and the fourth sheet S34 have the same size as the first sheet S21 and the second sheet S22. In other words, in the cushioning material 200, the first sheet S21, the second sheet S22, the first sheet S31, the second sheet S32, the third sheet S33, and the fourth sheet S34 are common parts.

[0218] The fifth sheet S35 and the sixth sheet S36 have the same shape. The fifth sheet S35 and the sixth sheet S36 have the same size. In other words, the fifth sheet S35 and the sixth sheet S36 are common parts in the second cushioning material 202. The seventh sheet S37 and the eighth sheet S38 have the same shape. The seventh sheet S37 and the eighth sheet S38 have the same size. In other words, the seventh sheet S37 and the eighth sheet S38 are common parts in the second cushioning material 202.

[0219] As shown in FIG. 9A, each of the first sheet S31, the second sheet S32, the third sheet S33, and the fourth sheet S34 has a first extending portion 110 and a second extending portion 120. The first extending portion 110 has a first outer edge 111, a first inner edge 112, and an inner slit 113. The second extending portion 120 has a second outer edge 121, a second inner edge 122, and an outer slit 123.

[0220] As shown in FIG. 14A, each of the fifth sheet S35 and the sixth sheet S36 has a third extending portion 230, a fourth extending portion 240, and a fifth extending portion 250. The third extending portion 230 has a third outer edge 231, a third inner edge 232, a first inner slit 233A, and a second inner slit 233B. The fourth extending portion 240 has a fourth outer edge 241, a fourth inner edge 242, and a first outer slit 243. The fifth extending portion 250 has a fifth outer edge 251, a fifth inner edge 252, and a second outer slit 253.

[0221] In the embodiment, each of the fifth sheet S35 and the sixth sheet S36 has a shape symmetrical with respect to the center in the cross direction.

[0222] As shown in FIG. 14B, each of the seventh sheet S37 and the eighth sheet S38 has a U-shape, and has a sixth extending portion 260, a seventh extending portion 270, and an eighth extending portion 280. Each of the sixth extending portion 260 and the seventh extending portion 270 extends in the cross direction. The eighth extending portion 280 extends in the flute direction. The eighth extending portion 280 connects one end portion of the sixth extending portion 260 in the cross direction and one end portion of the seventh extending portion 270 in the cross direction.

[0223] The sixth extending portion 260 has a sixth outer edge 261, a sixth inner edge 262 opposite to the sixth outer edge 261, and a first inner slit 263. The sixth outer edge 261 is an outer edge of the sixth extending portion 260 and contacts the inner surface 11 of the packaging box 10. The sixth inner edge 262 is an inner edge of the sixth extending portion 260 and faces the object to be packaged 20.

[0224] The sixth extending portion 260 has a protruding portion 264 on the sixth outer edge 261. The protruding portion 264 is a portion that contacts the inner surface 11 of the packaging box 10, and protrudes toward the inner surface 11 of the packaging box 10. Specifically, the protruding portion 264 protrudes in the flute direction. The protruding portion 264 has a contact surface 265 that contacts the inner surface 11 of the packaging box 10.

[0225] The first inner slit 263 extends in the flute direction from the sixth inner edge 262 toward the sixth outer edge 261. Specifically, the first inner slit 263 extends in the flute direction from the sixth inner edge 262 toward the contact surface 265 of the protruding portion 264.

[0226] The seventh extending portion 270 has a seventh outer edge 271, a seventh inner edge 272 opposite to the seventh outer edge 271, and a second inner slit 273. The seventh outer edge 271 is an outer edge of the seventh extending portion 270 and contacts the inner surface 11 of the packaging box 10. The seventh inner edge 272 is an inner edge of the seventh extending portion 270 and faces the object to be packaged 20.

[0227] The seventh extending portion 270 has a protruding portion 274 on the seventh outer edge 271. The protruding portion 274 is a portion that contacts the inner surface 11 of the packaging box 10, and protrudes toward the inner surface 11 of the packaging box 10. Specifically, the protruding portion 274 protrudes in the flute direction. The protruding portion 274 has a contact surface 275 that contacts the inner surface 11 of the packaging box 10.

[0228] The second inner slit 273 extends in the flute direction from the seventh inner edge 272 toward the seventh outer edge 271. Specifically, the second inner slit 273 extends in the flute direction from the seventh inner edge 272 toward the contact surface 275 of the protruding portion 274.

[0229] The eighth extending portion 280 has an eighth outer edge 281, an eighth inner edge 282 opposite to the eighth outer edge 281, a first outer slit 283A, and a second outer slit 283B. The eighth outer edge 281 is an outer edge of the eighth extending portion 280 and contacts the inner surface 11 of the packaging box 10. The eighth inner edge 282 is an inner edge of the eighth extending portion 280 and faces the object to be packaged 20.

[0230] The eighth outer edge 281 has protruding portions 284A and 284B. The protruding portions 284A and 284B are portions capable of contacting the inner surface 11 of the packaging box 10. The protruding portion 284A protrudes from an end portion of the eighth extending portion 280 in the flute direction, which is close to the sixth extending portion 260, toward the inner surface 11 of the packaging box 10. The protruding portion 284B protrudes from an end portion of the eighth extending portion 280 in the flute direction, which is close to the seventh extending portion 270, toward the inner surface 11 of the packaging box 10.

[0231] The protruding portions 284A and 284B protrude in the cross direction. The protruding portion 284A has a contact surface 285A capable of contacting the inner surface 11 of the packaging box 10. The protruding portion 284B has a contact surface 285B capable of contacting the inner surface 11 of the packaging box 10.

[0232] The first outer slit 283A extends in the cross direction from an end portion of the eighth outer edge 281 which is close to the sixth extending portion 260. Specifically, the first outer slit 283A extends from the contact surface 285A toward the eighth inner edge 282 in the cross direction. The second outer slit 283B extends in the cross direction from an end portion of the eighth outer edge 281 which is close to the seventh extending portion 270. Specifically, the second outer slit 283B extends from the contact surface 285B toward the eighth inner edge 282 in the cross direction.

[0233] In the embodiment, each of the seventh sheet S37 and the eighth sheet S38 has a shape symmetrical with respect to the center in the flute direction.

[0234] In the second cushioning material 202, the inner slit 113 of the first sheet S31 and the first outer slit 243 of the fifth sheet S35 are engaged with each other, the first inner slit 233A of the fifth sheet S35 and the first outer slit 283A of the seventh sheet S37 are engaged with each other, and the first inner slit 263 of the seventh sheet S37 and the outer slit 123 of the first sheet S31 are engaged with each other. In the second cushioning material 202, the inner slit 113 of the second sheet S32 and the second outer slit 253 of the fifth sheet S35 are engaged with each other, the second inner slit 233B of the fifth sheet S35 and the first outer slit 283A of the eighth sheet S38 are engaged with each other, and the first inner slit 263 of the eighth sheet S38 and the outer slit 123 of the second sheet S32 are engaged with each other.

[0235] In the second cushioning material 202, the inner slit 113 of the third sheet S33 and the first outer slit 243 of the sixth sheet S36 are engaged with each other, the first inner slit 233A of the sixth sheet S36 and the second outer slit 283B of the seventh sheet S37 are engaged with each other, and the second inner slit 273 of the seventh sheet S37 and the outer slit 123 of the third sheet S33 are engaged with each other. In the second cushioning material 202, the inner slit 113 of the fourth sheet S34 and the second outer slit 253 of the sixth sheet S36 are engaged with each other, the second inner slit 233B of the sixth sheet S36 and the second outer slit 283B of the eighth sheet S38 are engaged with each other, and the second inner slit 273 of the eighth sheet S38 and the outer slit 123 of the fourth sheet S34 are engaged with each other.

[0236] As shown in FIGS. 12, 13, and 15, the second cushioning material 202 contacts the five inner surfaces 11 of the packaging box 10. Specifically, as shown in FIG. 15, in the second cushioning material 202, the contact surface 115 of the first sheet S31 contacts the inner surface 11A of the packaging box 10, and the contact surface 125 contacts the inner surface 11C of the packaging box 10. In the second cushioning material 202, the contact surface 115 of the second sheet S32 contacts the inner surface 11D of the packaging box 10, and the contact surface 125 contacts the inner surface 11C of the packaging box 10.

[0237] In the second cushioning material 202, the contact surface 115 of the third sheet S33 contacts the inner surface 11A of the packaging box 10, and the contact surface 125 contacts an inner surface 11E of the packaging box 10 adjacent to the inner surface 11A, 11B, and 11D. In the second cushioning material 202, the contact surface 115 of the fourth sheet S34 contacts the inner surface 11D of the packaging box 10, and the contact surface 125 contacts the inner surface 11E of the packaging box 10.

[0238] As shown in FIG. 13, in the second cushioning material 202, each of the contact surfaces 235A and 235B of the fifth sheet S35 and the sixth sheet S36 contacts an inner surface 11F of the packaging box 10 adjacent to the inner surfaces 11A, 11C, and 11D. The fourth outer edge 241 of the fifth sheet S35 and the sixth sheet S36 does not contact the inner surface 11A of the packaging box 10. The fifth outer edge 251 of the fifth sheet S35 and the sixth sheet S36 does not contact the inner surface 11D of the packaging box 10.

[0239] As shown in FIG. 12, in the second cushioning material 202, the contact surface 265 of the seventh sheet S37 and the eighth sheet S38 contacts the inner surface 11C of the packaging box 10, and the contact surface 275 contacts the inner surface 11E of the packaging box 10. In the second cushioning material 202, each of the contact surfaces 285A and 285B of the seventh sheet S37 and the eighth sheet S38 contacts the inner surface 11F of the packaging box 10.

[0240] In the second cushioning material 202, the first sheet S31 corresponds to a "first corrugated cardboard sheet", for example. The first outer edge 111 of the first sheet S31 corresponds to a "first edge", the protruding portion 114 corresponds to a "first protruding portion", the contact surface 115 corresponds to a "first contact surface", the first inner edge 112 corresponds to a "fourth edge", and the inner slit 113 corresponds to a "first slit". The inner surface 11 of the packaging box 10 facing the first outer edge 111 of the first sheet S31 corresponds to a "first inner surface".

[0241] The fifth sheet S35 corresponds to a "second corrugated cardboard sheet". The third outer edge 231 of the fifth sheet S35 corresponds to a "second edge", the protruding portion 234A corresponds to a "second protruding portion", the fourth outer edge 241 corresponds to a "fifth edge", the fourth inner edge 242 corresponds to a "sixth edge", and the first outer slit 243 corresponds to a "second slit". The inner surface 11 of the packaging box 10 facing the third outer edge 231 of the fifth sheet S35 corresponds to a "second inner surface".

[0242] The seventh sheet S37 corresponds to a "third corrugated cardboard sheet". The sixth outer edge 261 of the seventh sheet S37 corresponds to a "third edge", and the protruding portion 264 corresponds to a "third protruding portion". The inner surface 11 of the packaging box 10 facing the sixth outer edge 261 of the seventh sheet S37 corresponds to a "third inner surface".

[0243] As shown in FIGS. 7 and 8, the intermediate sheet 300 is disposed between the cushioning material 200 and the object to be packaged 20. Specifically, the first intermediate sheet 310 is disposed between the first cushioning material 201 and the object to be packaged 20. The second intermediate sheet 320 is disposed between the second cushioning material 202 and the object to be packaged 20.

[0244] The first intermediate sheet 310 and the second intermediate sheet 320 are formed of corrugated cardboard sheets. Specifically, the first intermediate sheet 310 and the second intermediate sheet 320 are formed by folding a corrugated cardboard sheet.

[0245] The first intermediate sheet 310 has a top plate 311 and a plurality of side plates 312 extending downward from the periphery of the top plate 311. The plurality of side plates 312 include a plurality of first side plates 312A facing each other in a direction in which the third extending portion 230 of the fifth sheet S25 extends, and a plurality of second side plates 312B facing each other in a direction in which the two first cushioning materials 201 face each other.

[0246] The second intermediate sheet 320 has a bottom plate 321 and a plurality of side plates 322 extending upward from the periphery of the bottom plate 321. The plurality of side plates 322 include a plurality of third side plates 322A facing each other in a direction in which the third extending portion 230 of the sheets S35 and S36 extends, and a plurality of fourth side plates 322B facing each other in a direction in which the eighth extending portion 280 of the sheets S37 and S38 extends.

[0247] As shown in FIG. 11, in the first intermediate sheet 310, the first side plate 312A is disposed between the first inner edge 112 of the sheets S21 and S22 constituting the first cushioning material 201 and the object to be packaged 20. In the first intermediate sheet 310, the second side plate 312B is disposed between the second inner edge 122 of the sheets S21 and S22 and the object to be packaged 20.

[0248] As shown in FIG. 12, in the first intermediate sheet 310, the second side plate 312B is disposed between the first inner edge 112 of the sheets S23 and S24 constituting the first cushioning material 201 and the object to be packaged 20. In the first intermediate sheet 310, the top plate 311 is disposed between the second inner edges 122 of the sheets S23 and S24 and the object to be packaged 20. In the second intermediate sheet 320, the bottom plate 321 is disposed between the eighth inner edge 282 of the sheets S37 and S38 constituting the second cushioning material 202 and the object to be packaged 20. In the second intermediate sheet 320, the fourth side plate 322B is disposed between the inner edges 262 and 272 of the sheets S37 and S38 and the object to be packaged 20.

[0249] As shown in FIG. 13, in the first intermediate sheet 310, the top plate 311 is disposed between the third inner edge 232 of the fifth sheet S25 constituting the first cushioning material 201 and the object to be packaged 20. In the first intermediate sheet 310, the first side plate 312A is disposed between the inner edges 242 and 252 of the fifth sheet S25 and the object to be packaged 20. In the second intermediate sheet 320, the bottom plate 321 is disposed between the third inner edge 232 of the sheets S35 and S36 constituting the second cushioning material 202 and the object to be packaged 20. In the second intermediate sheet 320, the third side plate 322A is disposed between the inner edges 242 and 252 of the sheets S35 and S36 and the object to be packaged 20.

[0250] As shown in FIG. 15, in the second intermediate sheet 320, the third side plate 322A is disposed between the first inner edge 112 of the sheets S31 to S34 constituting the second cushioning material 202 and the object to be packaged 20. In the second intermediate sheet 320, the fourth side plate 322B is disposed between the second inner edge 122 of the sheets S31 to S34 and the object to be packaged 20.

[0251] Next, the effects of the cushioning material 200 will be described.

[0252] Since the first cushioning material 201 is formed by engaging the sheets S21 to S25 with one another, the first cushioning material 201 is less likely to be disassembled even when an impact is received from any direction. This can improve the cushioning performance. The fifth sheet S25 can suppress the first cushioning material 201 from falling.

[0253] The first cushioning material 201 can reduce the number of parts constituting the packaging material 2. For example, when the cushioning material 100 of the first embodiment is used in the upper part of the packaging box 10, four cushioning materials 100 are required, and the number of parts is 12. Since the number of parts is reduced to ten by using two first cushioning materials 201, the number of parts can be reduced.

[0254] Since the sheets S21 and S22 have the same shape and the sheets S23 and S24 have the same shape, the number of types of parts constituting the first cushioning material 201 can be reduced.

[0255] Since the "second direction" is the flute direction of the corrugated cardboard sheet, the strength of each of the sheets S21 to S25 in the "second direction" can be increased. Accordingly, the first cushioning material 201 in which the plurality of sheets S21 to S25 are assembled can firmly receive an impact even when the impact is received from any direction.

[0256] Since the second cushioning material 202 is formed by engaging the sheets S31 to S38 with one another, the second cushioning material 202 is less likely to be disassembled even when an impact is received from any direction. This can improve the cushioning performance.

[0257] The second cushioning material 202 can reduce the number of parts constituting the packaging material 2. For example, when the cushioning material 100 of the first embodiment is used in the lower part of the packaging box 10, four cushioning materials 100 are required, and the number of parts is 12. When the first cushioning material 201 is used in the lower part of the packaging box 10, two first cushioning materials 201 are required, and the number of parts is 10. Since the number of parts is reduced to eight by using the second cushioning material 202, the number of parts can be reduced.

[0258] Since the sheets S31 to S34 have the same shape, the sheets S35 and S36 have the same shape, and the sheets S37 and S38 have the same shape, the number of types of parts constituting the second cushioning material 202 can be reduced.

[0259] Since the "second direction" is the flute direction of the corrugated cardboard sheet, the strength of each of the sheets S31 to S38 in the "second direction" can be increased. Accordingly, the second cushioning material 202 in which the plurality of sheets S31 to S38 are assembled can firmly receive an impact even when the impact is received from any direction.

[0260] Since the dimension D2 from the first inner edge 112 to the contact surface 115 is greater than the sum of the length L3 of the inner slit 113 and the length L4 of the first outer slit 243, when the inner slit 113 and the first outer slit 243 are engaged with each other, the first outer edge 111 protrudes farther toward the inner surface 11 of the packaging box 10 than the fourth outer edge 241. This ensures that the first outer edge 111 contacts the inner surface 11 of the packaging box 10. In other words, since the fourth outer edge 241 is separated from the inner surface 11 of the packaging box 10, the contact surface 115 reliably contacts the first inner surface of the packaging box 10.

[0261] Since the dimension D2 from the first inner edge 112 to the contact surface 115 is greater than the sum of the length L3 of the inner slit 113 and the length L4 of the second outer slit 253, when the inner slit 113 and the second outer slit 253 are engaged with each other, the first outer edge 111 protrudes farther toward the inner surface 11 of the packaging box 10 than the fifth outer edge 251. This ensures that the first outer edge 111 contacts the inner surface 11 of the packaging box 10. In other words, since the fifth outer edge 251 is separated from the inner surface 11 of the packaging box 10, the contact surface 115 reliably contacts the first inner surface of the packaging box 10.

[0262] The fourth outer edge 241 may have a protruding portion (fourth protruding portion) that protrudes toward the inner surface 11 of the packaging box 10, and the protruding portion may have a contact surface (second contact surface) capable of contacting the inner surface 11 of the packaging box 10. In this case, the contact surface of the protruding portion of the fourth outer edge may be separated from the inner surface 11 of the packaging box 10. This also ensures that the first outer edge 111 contacts the inner surface 11 of the packaging box 10. The same applies to the fifth outer edge 251.

[0263] Since the packaging material 2 includes the intermediate sheet 300 disposed between the cushioning material 200 and the object to be packaged 20, the cushioning material 200 and the object to be packaged 20 do not directly contact each other. This can improve the cushioning performance.

[0264] Since the sheets S21, S22, and S31 to S34 have the reinforcement portions 142 that contact the two adjacent inner surfaces 11, 11 forming the corner portion 12 of the packaging box 10, the corner portion of the packaging box 10 can be reinforced from the inside by the sheets S21, S22, and S31 to S34.

[0265] Although the embodiments have been described above, the cushioning material can be appropriately modified as exemplified below.

[0266] In the above embodiment, the intermediate sheet 300 made of a corrugated cardboard sheet is illustrated, but the intermediate sheet may be, for example, a resin bag, a resin sheet, and so on that is covered on the object to be packaged.

[0267] In the above embodiment, the inner edges (edges facing the object to be packaged) of the sheets S11 to S13, S21 to S25, and S31 to S38 are flat, but for example, the edges of the sheets facing the object to be packaged may have irregularities in accordance with the shape of the object to be packaged.

[0268] In the above embodiment, the sheets S11 to S13 are common parts and have the same shape, but at least one of the first sheet, the second sheet, and the third sheet may not be a common part. That is, the shape may be different. For example, only two or one of the first sheet, the second sheet, and the third sheet may have a recessed portion at a position facing the corner portion of the packaging box, the recessed portion having a shape recessed in a direction away from the corner portion of the packaging box.

[0269] For example, only two or one of the first sheet, the second sheet, and the third sheet may have a configuration in which a protruding portion is provided at the outer edge of the first extending portion. In this case, only the sheet having the protruding portion may have a flat portion.

[0270] The same applies to the sheets S21 and S22, the sheets S23 and S24, the sheets S31 to S34, the sheets S35 and S36, and the sheets S37 and S38, and the shape may not be the same.

[0271] In the above embodiment, the cushioning material 100 is configured to contact the three inner surfaces 11 (11A, 11B, 11C) of the packaging box 10, but the cushioning material may be configured to contact only two adjacent inner surfaces of the packaging box, for example.

[0272] In the above embodiment, the cushioning material is assembled by engaging the slits of the plurality of sheets with each other, but the cushioning material may be assembled by bonding the plurality of sheets with an adhesive and so on, for example. The cushioning material may be assembled by joining a plurality of sheets with a stapler and so on. The cushioning material may be assembled by folding and connecting a plurality of sheets to each other.

[0273] In the above embodiment, the sheets S11 to S13, S21 to S25, and S31 to S38 are formed of corrugated cardboard sheets, but the sheets may be formed of pulp molds obtained by molding pulp such as used paper in a mold. The sheet may be made of foamed polystyrene.

[0274] In order to prevent the cushioning material from falling, for example, the cushioning material may be attached to the inner surface of the packaging box. For example, the cushioning material may be engaged with a groove and so on provided on the inner surface of the packaging box.

[0275] The elements described in the above embodiments and modifications may be implemented in any combination.REFERENCE SIGNS LIST

[0276] 1 Packaging material 10 Packaging box 11 Inner surface 20 Object to be packaged 100 Cushioning material 110 First extending portion 111 First outer edge 112 First inner edge 113 Inner slit 120 Second extending portion 121 Second outer edge 123 Outer slit S11 First sheet S12 Second sheet S13 Third sheet

Claims

1. A cushioning material comprising a first sheet, a second sheet, and a third sheet, the cushioning material being disposed between an object to be packaged and a packaging box accommodating the object to be packaged, each of the first sheet, the second sheet, and the third sheet having: a first extending portion; and a second extending portion extending in a second direction from one end portion of the first extending portion in a first direction in which the first extending portion extends, the second direction being perpendicular to the first direction, the first extending portion having: an outer edge that contacts an inner surface of the packaging box; an inner edge that faces the object to be packaged, the inner edge being opposite to the outer edge of the first extending portion; and an inner slit extending in the second direction from the inner edge of the first extending portion, the second extending portion having: an outer edge that faces an inner surface of the packaging box so as to be contactable with the inner surface of the packaging box; and an outer slit extending in the first direction from the outer edge of the second extending portion, the inner slit of the first sheet and the outer slit of the second sheet being engaged with each other, the inner slit of the second sheet and the outer slit of the third sheet being engaged with each other, the inner slit of the third sheet and the outer slit of the first sheet being engaged with each other.

2. The cushioning material according to claim 1, wherein at least one of the first sheet, the second sheet, and the third sheet has a protruding portion on the outer edge of the first extending portion, the protruding portion protruding in the second direction to contact an inner surface of the packaging box.

3. The cushioning material according to claim 2, wherein each of the first sheet, the second sheet, and the third sheet has the protruding portion on the outer edge of the first extending portion.

4. The cushioning material according to claim 2 or 3, wherein the protruding portion has a contact surface that contacts an inner surface of the packaging box; and wherein the outer edge of the first extending portion having the protruding portion has a flat portion that is farther from an inner surface of the packaging box than the contact surface.

5. The cushioning material according to claim 4, wherein the outer edge of the first extending portion having the protruding portion and the flat portion has a connection portion that connects the contact surface and the flat portion, the connection portion being inclined with respect to the flat portion; and wherein a size of the protruding portion in the first direction increases toward the flat portion in the second direction.

6. The cushioning material according to claim 2 or 3, wherein at least one of the first sheet, the second sheet, and the third sheet has a recessed portion at a position facing a corner portion formed between two inner surfaces of the packaging box, the recessed portion having a shape recessed in a direction away from the corner portion of the packaging box.

7. The cushioning material according to claim 1, wherein the second extending portion has an inner edge that faces the object to be packaged, the inner edge being opposite to the outer edge of the second extending portion; wherein the inner edge of the first extending portion is flat; and wherein the inner edge of the second extending portion is flat.

8. The cushioning material according to claim 1, wherein the cushioning material has an opening capable of receiving a corner portion of the object to be packaged.

9. The cushioning material according to claim 1, wherein the first sheet, the second sheet, and the third sheet have a same shape.

10. The cushioning material according to claim 1, wherein the first sheet, the second sheet, and the third sheet are formed of corrugated cardboard sheets; wherein the first direction is a cross direction of a corrugated cardboard sheet; and wherein the second direction is a flute direction of a corrugated cardboard sheet.

11. A cushioning material comprising a first sheet, a second sheet, a third sheet, a fourth sheet, and a fifth sheet, the cushioning material being disposed between an object to be packaged and a packaging box accommodating the object to be packaged, each of the first sheet, the second sheet, the third sheet, and the fourth sheet having: a first extending portion; and a second extending portion extending in a second direction from one end portion of the first extending portion in a first direction in which the first extending portion extends, the second direction being perpendicular to the first direction, the first extending portion having: an outer edge that contacts an inner surface of the packaging box; an inner edge that faces the object to be packaged, the inner edge being opposite to the outer edge of the first extending portion; and an inner slit extending in the second direction from the inner edge of the first extending portion, the second extending portion having: an outer edge that faces an inner surface of the packaging box so as to be contactable with the inner surface of the packaging box; and an outer slit extending in the first direction from the outer edge of the second extending portion, the fifth sheet having: a third extending portion extending in the first direction; a fourth extending portion extending in the second direction from one end portion of the third extending portion in the first direction; and a fifth extending portion extending in the second direction from another end portion of the third extending portion in the first direction, the third extending portion having: an outer edge that contacts an inner surface of the packaging box; an inner edge that faces the object to be packaged, the inner edge being opposite to the outer edge of the third extending portion; a first inner slit extending in the second direction from an end portion of the inner edge of the third extending portion, the end portion being close to the fourth extending portion; and a second inner slit extending in the second direction from an end portion of the inner edge of the third extending portion, the end portion being close to the fifth extending portion, the fourth extending portion having: an outer edge that faces an inner surface of the packaging box so as to be contactable with the inner surface of the packaging box; and a first outer slit extending in the first direction from the outer edge of the fourth extending portion, the fifth extending portion having: an outer edge that faces an inner surface of the packaging box so as to be contactable with the inner surface of the packaging box; and a second outer slit extending in the first direction from the outer edge of the fifth extending portion, the inner slit of the first sheet and the first outer slit of the fifth sheet being engaged with each other, the first inner slit of the fifth sheet and the outer slit of the third sheet being engaged with each other, the inner slit of the third sheet and the outer slit of the first sheet being engaged with each other, the inner slit of the second sheet and the second outer slit of the fifth sheet being engaged with each other, the second inner slit of the fifth sheet and the outer slit of the fourth sheet being engaged with each other, the inner slit of the fourth sheet and the outer slit of the second sheet being engaged with each other.

12. The cushioning material according to claim 11, wherein the first sheet and the second sheet have a same shape; and wherein the third sheet and the fourth sheet have a same shape.

13. The cushioning material according to claim 11 or 12, wherein the first sheet, the second sheet, the third sheet, the fourth sheet, and the fifth sheet are formed of corrugated cardboard sheets; wherein the first direction is a cross direction of a corrugated cardboard sheet; and wherein the second direction is a flute direction of a corrugated cardboard sheet.

14. A cushioning material comprising a first sheet, a second sheet, a third sheet, a fourth sheet, a fifth sheet, a sixth sheet, a seventh sheet, and an eighth sheet, the cushioning material being disposed between an object to be packaged and a packaging box accommodating the object to be packaged, each of the first sheet, the second sheet, the third sheet, and the fourth sheet having: a first extending portion; and a second extending portion extending in a second direction from one end portion of the first extending portion in a first direction in which the first extending portion extends, the second direction being perpendicular to the first direction, the first extending portion having: an outer edge that contacts an inner surface of the packaging box; an inner edge that faces the object to be packaged, the inner edge being opposite to the outer edge of the first extending portion; and an inner slit extending in the second direction from the inner edge of the first extending portion, the second extending portion having: an outer edge that faces an inner surface of the packaging box so as to be contactable with the inner surface of the packaging box; and an outer slit extending in the first direction from the outer edge of the second extending portion, each of the fifth sheet and the sixth sheet having: a third extending portion extending in the first direction; a fourth extending portion extending in the second direction from one end portion of the third extending portion in the first direction; and a fifth extending portion extending in the second direction from another end portion of the third extending portion in the first direction, the third extending portion having: an outer edge that contacts an inner surface of the packaging box; an inner edge that faces the object to be packaged, the inner edge being opposite to the outer edge of the third extending portion; a first inner slit extending in the second direction from an end portion of the inner edge of the third extending portion, the end portion being close to the fourth extending portion; and a second inner slit extending in the second direction from an end portion of the inner edge of the third extending portion, the end portion being close to the fifth extending portion, the fourth extending portion having: an outer edge that faces an inner surface of the packaging box so as to be contactable with the inner surface of the packaging box; and a first outer slit extending in the first direction from the outer edge of the fourth extending portion, the fifth extending portion having: an outer edge that faces an inner surface of the packaging box so as to be contactable with the inner surface of the packaging box; and a second outer slit extending in the first direction from the outer edge of the fifth extending portion, each of the seventh sheet and the eighth sheet having: a sixth extending portion extending in the first direction; a seventh extending portion extending in the first direction; and an eighth extending portion extending in the second direction and connecting one end portion of the sixth extending portion in the first direction and one end portion of the seventh extending portion in the first direction, the sixth extending portion having: an outer edge that contacts an inner surface of the packaging box; an inner edge that faces the object to be packaged, the inner edge being opposite to the outer edge of the sixth extending portion; and a first inner slit extending in the second direction from the inner edge of the sixth extending portion, the seventh extending portion having: an outer edge that contacts an inner surface of the packaging box; an inner edge that faces the object to be packaged, the inner edge being opposite to the outer edge of the seventh extending portion; and a second inner slit extending in the second direction from the inner edge of the seventh extending portion, the eighth extending portion having: an outer edge that contacts an inner surface of the packaging box; a first outer slit extending in the first direction from an end portion of the outer edge of the eighth extending portion, the end portion being close to the sixth extending portion; and a second outer slit extending in the first direction from an end portion of the outer edge of the eighth extending portion, the end portion being close to the seventh extending portion, the inner slit of the first sheet and the first outer slit of the fifth sheet being engaged with each other, the first inner slit of the fifth sheet and the first outer slit of the seventh sheet being engaged with each other, the first inner slit of the seventh sheet and the outer slit of the first sheet being engaged with each other, the inner slit of the second sheet and the second outer slit of the fifth sheet being engaged with each other, the second inner slit of the fifth sheet and the first outer slit of the eighth sheet being engaged with each other, the first inner slit of the eighth sheet and the outer slit of the second sheet being engaged with each other, the inner slit of the third sheet and the first outer slit of the sixth sheet being engaged with each other, the first inner slit of the sixth sheet and the second outer slit of the seventh sheet being engaged with each other, the second inner slit of the seventh sheet and the outer slit of the third sheet being engaged with each other, the inner slit of the fourth sheet and the second outer slit of the sixth sheet being engaged with each other, the second inner slit of the sixth sheet and the second outer slit of the eighth sheet being engaged with each other, the second inner slit of the eighth sheet and the outer slit of the fourth sheet being engaged with each other.

15. The cushioning material according to claim 14, wherein the first sheet, the second sheet, the third sheet, and the fourth sheet have a same shape; wherein the fifth sheet and the sixth sheet have a same shape; and wherein the seventh sheet and the eighth sheet have a same shape.

16. The cushioning material according to claim 14 or 15, wherein the first sheet, the second sheet, the third sheet, the fourth sheet, the fifth sheet, the sixth sheet, the seventh sheet, and the eighth sheet are formed of corrugated cardboard sheets; wherein the first direction is a cross direction of a corrugated cardboard sheet; and wherein the second direction is a flute direction of a corrugated cardboard sheet.

17. A packaging material comprising: the cushioning material according to any one of claims 1, 11, and 14; and an intermediate sheet disposed between the cushioning material and the object to be packaged.

18. The image forming apparatus according to claim 1, wherein a dimension from the outer edge to the inner edge of the first sheet is greater than or equal to a sum of the inner slit and the outer slit.

19. A cushioning material comprising a plurality of sheets, the cushioning material being formed by assembling the plurality of sheets, the cushioning material being disposed between an object to be packaged and a packaging box accommodating the object to be packaged, the cushioning material contacting at least a first inner surface of the packaging box and a second inner surface adjacent to the first inner surface of the packaging box, the plurality of sheets including a first corrugated cardboard sheet, the first corrugated cardboard sheet having a first edge that faces the first inner surface of the packaging box, the first edge having a first protruding portion that protrudes toward the first inner surface of the packaging box and that contacts the first inner surface of the packaging box.

20. The cushioning material according to claim 19, wherein the first protruding portion has a first contact surface that contacts the first inner surface of the packaging box; and wherein the first edge has a flat portion that is farther from the first inner surface of the packaging box than the first contact surface.

21. The cushioning material according to claim 20, wherein the first edge has a connection portion connecting the first contact surface and the flat portion, the connection portion being inclined with respect to the flat portion; and wherein a size of the first protruding portion in a direction perpendicular to a protruding direction in which the first protruding portion protrudes increases toward the flat portion in the protruding direction.

22. The cushioning material according to claim 19, wherein the plurality of sheets includes a second corrugated cardboard sheet; wherein the second corrugated cardboard sheet has a second edge that faces the second inner surface of the packaging box; and wherein the second edge has a second protruding portion that protrudes toward the second inner surface of the packaging box and that contacts the second inner surface of the packaging box.

23. The cushioning material according to claim 22, wherein the plurality of sheets includes a third corrugated cardboard sheet; wherein the third corrugated cardboard sheet has a third edge that faces a third inner surface adjacent to both the first inner surface and the second inner surface of the packaging box; and wherein the third edge has a third protruding portion that protrudes toward the third inner surface of the packaging box and that contacts the third inner surface of the packaging box.

24. The cushioning material according to any one of claims 19 to 23, wherein the first protruding portion protrudes in a flute direction of the first corrugated cardboard sheet.

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