Corrugated sheet material, corrugated spacer, and corrugated pallet

Abstract

To provide a corrugated cardboard sheet material that is suitable for use as a corrugated cardboard spacer or a corrugated cardboard girder and has good workability.SOLUTION: A corrugated cardboard sheet material 1 has an internal structure sheet portion 10 having four folds 11 to 14 extending in a direction perpendicular to a winding direction R, cuts 20 and 21 along the winding direction being provided between a first fold 11 and a second fold 12, with positions of the first fold and the second fold being offset at the cuts, a third fold 13 and a fourth fold 14 being arranged symmetrically with respect to an imaginary line V, and an exterior sheet portion having packaging folds 51 to 54.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cardboard sheet material that becomes a square tube shape by winding a sheet-like cardboard, a cardboard spacer made of this cardboard sheet material, and a cardboard pallet that uses this cardboard sheet material as a girder body.

Background Art

[0002] Wooden pallets are the mainstream for loading goods in logistics, but there are also environmental problems such as deforestation. Therefore, as described in Patent Documents 1 and 2 and Non-Patent Documents 1 and 2, the use of cardboard pallets, which are recyclable products, is increasing because they are lightweight and easy to discard. The basic configuration of this cardboard pallet consists of a cardboard deck board that serves as a loading surface and a cardboard girder body that supports the cardboard deck board. And, since the load concentrates on this cardboard girder body, strength and durability are required.

[0003] As a conventional cardboard girder body, there is known one in which cardboard is laminated as in Non-Patent Document 1 and Non-Patent Document 2 (TS pallet 203). However, such a girder body has a problem that the amount of cardboard used increases, resulting in an increase in weight and also an increase in the amount of waste after use.

[0004] Therefore, as in Non-Patent Document 2 (TS pallet 202), there is known a girder body composed of a tubular structure in which a cardboard sheet material is bent from both the left and right sides and a space is provided inside. Also, as in Patent Document 1, there is known a girder body formed with a plurality of inner cylinders (4) inside an outer cylinder (3) that forms the outer shape of the girder body.

[0005] In addition, a girder body such as that in Non-Patent Document 2 (TS pallet 202) can also be used as a spacer during packaging or mailing as in Patent Document 3 (the document published in Non-Patent Document 2) because it has sufficient strength.

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Document

[0007]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the case of a girder body such as that in Non-Patent Document 2, since it is necessary to wind the cardboard sheet material from both the left and right sides, after bending one side, then bending from the opposite side, there is a problem that the assembly work takes time. Also, in the case of girder bodies such as those in Patent Documents 1 and 2, since the work of bending a plurality of inner cylinders is required, there is also a problem that this also takes time for the assembly work.

[0009] Also, in the case of a cardboard spacer such as that in Patent Document 3, a plurality of them are required for use as a spacer. However, since the cardboard sheet material is wound from both the left and right sides, there is a problem that the work for each one also takes time.

[0010] Also, when using a forklift to move a cardboard pallet, the fork part can be inserted between adjacent cardboard girders, and the entire fork part can support the cardboard deck board and move it. However, since cardboard pallets are sometimes lightweight, they are often moved by hand. In this case, if the cardboard deck board is directly held by hand like a forklift, the area of the hand supporting the deck board is overwhelmingly smaller than that of the fork part, so a large force will be applied to the part where the hand touches. And if it is lifted and moved by hand many times, there is a problem that the part of the cardboard deck board will be damaged.

[0011] Therefore, an object is to provide a cardboard sheet material with good workability suitable for use as a cardboard spacer or a cardboard girder. Another object is to provide a cardboard spacer using this cardboard sheet material. Another object is to provide a cardboard pallet composed of cardboard girders using this cardboard sheet material.

Means for Solving the Problems

[0012] In order to solve the above problems, the corrugated sheet material of the present invention comprises a corrugated internal structure sheet portion forming a cylindrical structure, and a corrugated exterior sheet portion that continues from the internal structure sheet portion and wraps the structure. It is a corrugated sheet material that becomes a square tube shape by winding from the side of the internal structure sheet portion to the side of the exterior sheet portion. The internal structure sheet portion has four first to fourth creases extending in a direction perpendicular to the winding direction. The four first to fourth creases are the first crease, the second crease, the third crease, and the fourth crease from the upstream side which is the starting side of winding. A plurality of cuts along the winding direction are provided between the first crease and the second crease. With the cuts as a boundary, the positions of the first crease and the second crease are shifted downstream between the first crease and the second crease. The third crease and the fourth crease are provided symmetrically with respect to a straight line connecting the midpoints between the second crease and the third crease. The exterior sheet portion has a plurality of packaging creases extending in a direction perpendicular to the winding direction in order to wrap the structure formed by the internal structure sheet portion.

[0013] When the corrugated sheet material of the present invention is wound while being bent from the internal structure sheet portion toward the exterior sheet portion, it becomes a square tube-shaped member. Therefore, it has sufficient strength, good workability, and the time required for assembly is shortened, making it suitable for use as a corrugated spacer or a corrugated girder.

[0014] Further, in the corrugated sheet material of the present invention, a plurality of the cuts along the winding direction are alternately provided with a right-inclined cut inclined to the right direction and a left-inclined cut inclined to the left direction with respect to the winding direction. Due to the alternately provided right-inclined cuts and left-inclined cuts, the first crease and the second crease that are shifted with the cuts as a boundary are such that the first crease is longer than the second crease at the first crease and the second crease located upstream, and the first crease is shorter than the second crease at the first crease and the second crease located downstream, which is preferable.

[0015] When the corrugated sheet material of the present invention is wound from the internal structure sheet portion toward the exterior sheet portion, during the winding operation in the internal structure sheet portion, the force repelling in the winding direction can be suppressed, so that the workability is better.

[0016] Further, in the corrugated sheet material of the present invention, the exterior sheet portion preferably includes a first exterior surface covering between the first fold line and the second fold line, a second exterior surface covering between the second fold line and the third fold line, a third exterior surface covering between the third fold line and the fourth fold line, and a fourth exterior surface covering between the fourth fold line and the first fold line.

[0017] The corrugated sheet material of the present invention can cover the four surfaces of the square tube-shaped member with the exterior surfaces, so it is very suitable for use as a corrugated spacer or a corrugated girder that requires strength and durability.

[0018] Further, the corrugated spacer of the present invention is characterized by being made of the corrugated sheet material of the present invention. By using the corrugated sheet material as a corrugated spacer, it is very suitable as a spacer that requires strength and quantity. Also, for corrugated girders and corrugated spacers such as those in Patent Documents 1 to 3 and Non-Patent Documents 1 and 2, it is difficult to miniaturize structurally, but the corrugated spacer of the present invention that can be assembled only by winding in one direction is easy to miniaturize and is optimal even in cases where a small spacer is required.

[0019] Further, the corrugated pallet of the present invention is a corrugated pallet including a corrugated deck board serving as a loading surface and a plurality of corrugated girders supporting the corrugated deck board, and it is preferable to use the corrugated sheet material of the present invention as the corrugated girders.

[0020] The corrugated pallet of the present invention uses the corrugated sheet material of the present invention as the corrugated girders, so the assembly workability of the girders is good and it has sufficient strength.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0022] Hereinafter, the mode for carrying out the present invention will be described with reference to embodiments and drawings. However, the following embodiments are not intended to limit the present invention to what is described herein, and the present invention can be equally applied to those with various modifications without departing from the technical idea shown in the claims. In each drawing used for the description in this specification, in order to make each member recognizable on the drawing, the scale is made different for each member, and it is not necessarily shown in proportion to the actual dimensions.

[0023] [Embodiment] The corrugated cardboard sheet material 1 of the present embodiment will be described with reference to the drawings. FIG. 1A is a plan view of the corrugated cardboard sheet material 1 of the present embodiment, and FIG. 1B is a perspective view of the square tube-shaped member 100 formed by winding the corrugated cardboard sheet material 1.

[0024] The cardboard sheet material 1 is a rectangular sheet made of cardboard. The type of cardboard used is not limited, but in this embodiment, a double-sided cardboard with a core laminated between a front liner and a back liner is used. Note that Fig. 1A is a plan view seen from the back liner side. Also, in the cardboard sheet material 1 shown in Fig. 1A, the vertical direction of the paper surface is the so-called paper grain direction, and the horizontal direction is the so-called flow direction.

[0025] Then, with the paper grain direction from above to below in the paper surface of Fig. 1A as the winding direction R, the cardboard sheet material 1 is wound forward while being bent to form the square tube-shaped member 100 shown in Fig. 1B.

[0026] Such a cardboard sheet material 1 is rectangular and long in the winding direction R as shown in Fig. 1A. The first half of it is the internal structure sheet portion 10, and the remaining second half is the exterior sheet portion 50.

[0027] This internal structure sheet portion 10 forms a square tube-shaped structure 30 (shown in S2 of Fig. 2 to be described later) located inside the square tube-shaped member 100 by being wound forward while being bent.

[0028] More specifically, the internal structure sheet portion 10 has four folds: the first fold 11, the second fold 12, the third fold 13, and the fourth fold 14, which extend in a direction (flow direction) orthogonal to the winding direction R. These four folds 11 to 14 are, from the upstream side which is the starting side in the winding direction R, the first fold 11, the second fold 12, the third fold 13, and the fourth fold 14. Note that the folds described in this embodiment, such as the four folds 11 to 14, are formed by performing fold processing on the surface of the back liner and are shown by broken lines in Fig. 1 and the like.

[0029] Between the first fold line 11 and the second fold line 12, a plurality of (four in FIG. 1A) cuts are provided along the winding direction R. Specifically, these cuts consist of a right-inclined cut 20 that inclines to the right and a left-inclined cut 21 that inclines to the left with respect to the winding direction R, and the right-inclined cut 20 and the left-inclined cut 21 are provided alternately. Note that the cuts described in this embodiment, such as the right-inclined cut 20 and the left-inclined cut 21, are formed by cutting through the cardboard.

[0030] Then, with the right-inclined cut 20 or the left-inclined cut 21 as a boundary, as shown in FIG. 1A, the positions of the first fold line 11 and the second fold line 12 are shifted downstream between the first fold line 11 and the second fold line 12. Due to this shift, the first fold line 11 and the second fold line 12 are alternately divided into a first fold line 11u and a second fold line 12u located on the upstream side and a first fold line 11d and a second fold line 12d located on the downstream side, as shown in FIG. 1A.

[0031] On the other hand, the third fold line 13 and the fourth fold line 14 are line-symmetrical with respect to a virtual straight line V parallel to the flow direction connecting the midpoint between the second fold line 12 and the third fold line 13. Therefore, as shown in FIG. 1A, the formation order of the right-inclined cut 20 and the left-inclined cut 21 on the third fold line 13 and the fourth fold line 14 is opposite to the formation order of the right-inclined cut 20 and the left-inclined cut 21 on the first fold line 11 and the second fold line 12. And the positions of the third fold line 13 and the fourth fold line 14 are shifted upstream between the third fold line 13 and the fourth fold line 14, and due to this shift, the third fold line 13 and the fourth fold line 14 are alternately divided into a third fold line 13u and a fourth fold line 14u located on the upstream side and a third fold line 13d and a fourth fold line 14d located on the downstream side, as shown in FIG. 1A.

[0032] Note that the third fold 13 and the fourth fold 14 are line-symmetrical with respect to the virtual straight line V connecting the midpoints between the second fold 12 and the third fold 13. However, the line symmetry here does not mean that the shapes are exactly the same. Since the corrugated sheet material 1 will be wound forward, it is necessary to consider the thickness of the corrugated board. For example, the section between the first fold 11 and the second fold needs to be designed slightly shorter than the section between the third fold 13 and the fourth fold 14, and thus it is not line-symmetrical in the strict sense.

[0033] Also, two relief portions 15 are provided at the end of the internal structure sheet portion 10 where the winding in the winding direction R starts. These relief portions 15 are formed by notching the end of the corrugated board, and are provided such that the width in the flow direction is slightly longer than the length of the fourth fold 14d on the downstream side.

[0034] By winding and folding such an internal structure sheet portion 10 along the winding direction R, a square tube-shaped structure 30 located inside the cylindrical member 100 described later will be formed.

[0035] The exterior sheet portion 50 wraps the square tube-shaped structure 30 located inside the square tube-shaped member 100 by winding while folding. More specifically, since the exterior sheet portion 50 wraps the structure 30 composed of the internal structure sheet portion 10, it has four packaging folds: the first packaging fold 51, the second packaging fold 52, the third packaging fold 53, and the fourth packaging fold 54, which extend in the direction orthogonal to the winding direction R (flow direction). These four packaging folds 51 to 54 are, in the winding direction R, the first packaging fold 51, the second packaging fold 52, the third packaging fold 53, and the fourth packaging fold 54 from the upstream side.

[0036] And the area between the first packaging fold 51 and the second packaging fold 52 becomes the first exterior surface 61 that covers the area between the first fold 11 and the second fold 12 in the structure 30. Also, the area between the second packaging fold 52 and the third packaging fold 53 becomes the second exterior surface 62 that covers the area between the second fold 12 and the third fold 13 in the structure 30. Further, the area between the third packaging fold 53 and the fourth packaging fold 54 becomes the third exterior surface 63 that covers the area between the third fold 13 and the fourth fold 14 in the structure 30. And the area from the fourth packaging fold 54 to the end of the exterior sheet portion 50 becomes the fourth exterior surface 64 that covers the area between the fourth fold 14 and the first fold 11 in the structure 30 (the area between the end of the internal structure sheet portion 10 and the first fold 11, and the area between the fourth fold 14 and the first packaging fold 51).

[0037] Also, two lock recesses 55 are provided along the first packaging fold 51 on the exterior sheet portion 50, and two lock protrusions 56 are provided at the end which is the most downstream portion in the winding direction R. These lock recesses 55 are formed with cuts by cutting and serve as insertion openings for the lock protrusions 56.

[0038] By winding and advancing such an exterior sheet portion 50 along the winding direction R while folding it, the entire four surfaces of the rectangular tube-shaped structure 30 located inside the rectangular tube-shaped member 100 will be wrapped.

[0039] Next, the process until the rectangular tube-shaped member 100 is made from the corrugated cardboard sheet material 1 will be described with reference to the drawings. FIG. 2 is a process diagram showing a part of the process of advancing the corrugated cardboard sheet material 1.

[0040] First, regarding the cardboard sheet material 1 shown in FIG. 1A, valley folds are performed along the first fold lines 11 (11u, 11d) and the second fold lines 12 (12u, 12d) of the internal structure sheet portion 10 on the upstream side in the winding direction R, with the folds on the inner side. By folding the cardboard sheet material 1 in this way, the front liner side appears in the state shown in S1 of FIG. 2. That is, due to the deviation between the first fold line 11u (second fold line 12u) located on the upstream side and the first fold line 11d (second fold line 11d) located on the downstream side, the position deviates between the side surface 31 formed between the first fold line 11u and the second fold line 12u and the side surface 32 formed between the first fold line 11d and the second fold line 12d, and the opposing sides of each other intersect.

[0041] Next, from the state of S1, valley folds are performed along the third fold lines 13 (13u, 13d) and the fourth fold lines 14 (14u, 14d) of the internal structure sheet portion 10, with the folds on the inner side. By folding the cardboard sheet material 1 in this way, the state shown in S2 of FIG. 2 is obtained. That is, due to the deviation between the third fold line 13u (fourth fold line 14u) located on the upstream side and the third fold line 13d (fourth fold line 14d) located on the downstream side, the position deviates between the side surface 33 formed between the third fold line 13u and the fourth fold line 14u and the side surface 34 formed between the third fold line 13d and the fourth fold line 14d, and the opposing sides of each other intersect. And the rectangular tube-shaped structure 30 formed by the internal structure sheet portion 10 is completed. Such a structure 30 has sufficient strength not only against the force from the vertical direction but also against the forces in the winding direction R and the flow direction. Note that in the process of S2, due to the provision of the relief portion 15, the end portion of the internal structure sheet portion 10 and the side surface 34 do not interfere with each other.

[0042] Then, from the state of S2, next, along the first packaging fold 51 of the exterior sheet portion 50, a valley fold is performed with the fold on the inside, and subsequently, along the second packaging fold 52, a valley fold is performed, resulting in the state shown as S3 in FIG. 2. That is, the side surfaces 31, 32 formed by the first fold 11 and the second fold 12 in the structure 30 are covered by the first exterior surface 61 formed by the first packaging fold 51 and the second packaging fold 52, and the surface formed by the second fold 12 and the third fold 13 is covered by the second exterior surface 62 formed by the second packaging fold 52 and the third packaging fold 53.

[0043] From this state of S3, further, along the third packaging fold 53 of the exterior sheet portion 50, a valley fold is performed with the fold on the inside, and subsequently, along the fourth packaging fold 54, a valley fold is performed, resulting in the rectangular tubular member 100 shown in FIG. 1B. That is, the side surfaces 33, 34 formed by the third fold 13 and the fourth fold 14 in the structure 30 are covered by the third exterior surface 63 formed by the third packaging fold 53 and the fourth packaging fold 54, and the surface formed by the fourth fold 14 and the first fold 11 is covered by the fourth exterior surface 64 formed between the fourth packaging fold 54 and the end of the exterior sheet portion 50. Then, by inserting the lock convex portion 56 into the corresponding lock concave portion 55, the rectangular tubular member 100 formed by the internal structure sheet portion 10 is completed.

[0044] Such a rectangular tubular member 100 further covers the strong structure 30 on four more surfaces, so it becomes very strong. Also, the rectangular tubular member 100 is completed simply by advancing while folding the corrugated cardboard sheet material 1 in one direction along the winding direction R. Therefore, the corrugated cardboard sheet material 1 of the present embodiment does not require an operation such as changing the folding direction like a two-directional folding operation, and has very good workability.

[0045] In addition, in the corrugated cardboard sheet material of the present embodiment, in the completed rectangular tubular member 100, the lock convex portion 56 is inserted into the lock concave portion 55 and joined. Of course, an adhesive may be used to join more firmly. Also, instead of the configuration of the lock concave portion 55 and the lock convex portion 56, joining may be performed with an adhesive, or joining may be performed using corrugated cardboard staples.

[0046] In addition, in the corrugated sheet material 1 of the present embodiment, due to the alternately provided right inclined cuts 20 and left inclined cuts 21, the first fold line 11 and the second fold line 12 whose positions are shifted with these cuts as boundaries are, as shown in FIG. 1A, at the upstream first fold line 11u and the second fold line 12u, the first fold line 11u is longer than the second fold line 12u, and at the downstream first fold line 11d and the second fold line 12d, the first fold line 11d is shorter than the second fold line 12d.

[0047] With such a configuration, when the corrugated sheet material 1 is wound while being bent, during the bending operation in the internal structure sheet portion 10, the force that repels in the winding direction (the force to restore to the original sheet state) can be suppressed, so that the workability is better.

[0048] This point will be described in detail with reference to FIG. 3. A in FIG. 3 is a plan view and a reference image of the internal structure sheet portion 10 in the present embodiment, and B is a plan view of the internal structure sheet portion 10B shown for comparison. In the internal structure sheet portion 10B of FIG. 3B, the same reference numerals are given to the portions having the same configuration as the internal structure sheet portion 10 of FIG. 3A, and the same-named portions having different configurations are illustrated with the suffix "B" added to the reference numerals.

[0049] Here, the internal structure sheet portion 10 of FIG. 3A is the same as that shown in FIG. 1. Due to the alternately provided right inclined cuts 20 and left inclined cuts 21, the first fold line 11 and the second fold line 12 whose positions are shifted with these cuts as boundaries are, at the upstream first fold line 11u and the second fold line 12u, the first fold line 11u is longer than the second fold line 12u, and at the downstream first fold line 11d and the second fold line 12d, the first fold line 11d is shorter than the second fold line 12d.

[0050] The third fold 13 and the fourth fold 14 are symmetric with respect to a virtual straight line V parallel to the flow direction connecting the midpoints between the second fold 12 and the third fold 13. That is, in the upstream third fold 13u and fourth fold 14u, the third fold 13u is longer than the fourth fold 14u, and in the downstream third fold 13d and fourth fold 14d, the third fold 13d is shorter than the fourth fold 14d.

[0051] On the other hand, in the internal structure sheet portion 10B of FIG. 3B, the first fold 11B and the second fold 12B, which are alternately provided with right-angled cuts 20 and left-angled cuts 21 and are displaced in position with these cuts as boundaries, in the upstream first fold 11uB and second fold 12uB, the first fold 11uB is shorter than the second fold 12uB, and in the downstream first fold 11dB and second fold 12dB, the first fold 11dB is longer than the second fold 12dB.

[0052] The third fold 13B and the fourth fold 14B are symmetric with respect to a virtual straight line V parallel to the flow direction connecting the midpoints between the second fold 12B and the third fold 13B. That is, in the upstream third fold 13uB and fourth fold 14uB, the third fold 13uB is shorter than the fourth fold 14uB, and in the downstream third fold 13dB and fourth fold 14dB, the third fold 13dB is longer than the fourth fold 14dB.

[0053] At this time, in the internal structure sheet portion 10 shown in FIG. 3A, the trapezoid (side surface 31) composed of the first fold 11u with a long upper base and the second fold 12u with a short lower base becomes a downwardly convex trapezoid, and the trapezoid (side surface 32) composed of the first fold 11d with a short upper base and the second fold 12d with a long lower base becomes an upwardly convex trapezoid. Therefore, when folding, as in the reference image, the downwardly convex trapezoid (side surface 31) on the upstream side and the upwardly convex trapezoid (side surface 32) on the downstream side will approach each other in the vertical direction, and the opposing sides of the trapezoid (side surface 31) on the upstream side and the trapezoid (side surface 32) on the downstream side will come into contact. That is, the trapezoid (side surface 31) on the upstream side and the trapezoid (side surface 32) on the downstream side will closely engage with each other on the opposing sides.

[0054] This further increases the strength of the rectangular tubular structure 30, resulting in a very strong rectangular tubular member 100. In addition to this effect, since the side surfaces 31 and 32 engage with each other in the state shown in S1 of Fig. 2 by folding, this engagement can suppress the repulsive force in the winding direction (the force that tries to restore the internal structure sheet portion 10 to its original sheet-like state) during the folding operation, thereby improving workability.

[0055] 3B, the trapezoid (side surface 31B) formed by the first fold 11uB with a short upper base and the second fold 12uB with a long lower base is an upwardly convex trapezoid, and the trapezoid (side surface 32B) formed by the first fold 11dB with a long upper base and the second fold 12dB with a short lower base is a downwardly convex trapezoid. Therefore, as the sheet is folded, the upwardly convex trapezoid (side surface 31B) on the upstream side and the downwardly convex trapezoid (side surface 32B) on the downstream side approach each other in the vertical direction, but the opposing sides of the upstream trapezoid (side surface 31B) and the downstream trapezoid (side surface 32B) move away from each other.

[0056] Therefore, because side surface 31B and side surface 32B are not engaged but are separated, the force that suppresses the elastic restoring force generated by folding at first fold 11 and second fold 12 does not work, and the restoring force functions. For this reason, if you stop folding, the paper will return to its original state.

[0057] From the above, in this embodiment, the right-angled cut 20 and the left-angled cut 21 cause the first fold 11 and the second fold 12 to be misaligned at these cuts, and between the first fold 11u and the second fold u located upstream, the first fold 11u is longer than the second fold 12u, and between the first fold 11d and the second fold 12d located downstream, the first fold 11d is shorter than the second fold 12d.This configuration makes it easier to work with when the cardboard sheet material 1 is being folded and rolled up, as it can reduce the repulsive force in the rolling direction during the folding work at the internal structure sheet portion 10.

[0058] The corrugated cardboard sheet material 1 of this embodiment has sufficient strength when assembled into a rectangular tubular member 100, and is easy to assemble, allowing it to be assembled into a rectangular tubular member 100 in a short time. Therefore, the corrugated cardboard sheet material 1 is very suitable as a corrugated cardboard girder used in a corrugated cardboard spacer or a corrugated cardboard pallet. This point will be explained in detail.

[0059] [Cardboard spacer] Fig. 4 is a reference image for explaining an example of use of a square tubular member 100 assembled from the corrugated cardboard sheet material 1 of this embodiment as a corrugated cardboard spacer 101. Note that the corrugated cardboard spacer 101 shown in Fig. 4 is not made from the square tubular member 100 assembled from the corrugated cardboard sheet material 1 of this embodiment. This image is for showing that a corrugated cardboard spacer made from the square tubular member 100 can be used instead of the corrugated cardboard spacer 101 shown in Fig. 4.

[0060] As shown in Fig. 4A, a plurality of cardboard spacers 101 can be placed on a rectangular piece of cardboard C. The cardboard spacers 101 on the cardboard C are fixed to the surface of the cardboard C with adhesive. When such cardboard spacers 101 are used, for example, the cardboard spacers 101 can serve as a cushioning material made of a laminated core, and the cardboard C with the laminated core can be used to secure or underlay precision machinery or heavy machinery.

[0061] As shown in Fig. 4B, a plurality of cardboard spacers 101 can be arranged on the side of a box-shaped cardboard C. The cardboard spacers 101 on the side of the cardboard C are fixed to the side of the cardboard C with adhesive. When such cardboard spacers 101 are used, they function as spacers that restrict the movement of an object when the object is stored in the box-shaped cardboard C, for example.

[0062] As shown in Fig. 4C, a cardboard spacer 101 can be placed on the bottom surface of a box-shaped cardboard C, and an opening 102 can be provided in the surface of the cardboard spacer 101. When such a cardboard spacer 101 is used, for example, when an object with legs is stored in the cardboard box C, the legs of the object can be inserted into the opening 102, and the surface of the cardboard spacer 101 can support the bottom surface of the object, thereby functioning as a spacer that restricts movement of the stored object.

[0063] In this way, the rectangular tubular member 100 assembled from the corrugated cardboard sheet material 1 of this embodiment has sufficient strength and can be easily assembled, so it can be used as a corrugated cardboard spacer 101 as shown in Fig. 4. Furthermore, when used as shown in Fig. 4, the corrugated cardboard spacer 101 is often relatively small, for example, about 200 mm long in the machine direction. It is very difficult to create a spacer of this size with a structure such as that described in Patent Document 1, but a spacer made from the corrugated cardboard sheet material 1 of this embodiment can be easily miniaturized.

[0064] [Cardboard girder] 5 is a perspective view of a cardboard pallet P in which rectangular pillar-shaped members 100 assembled from cardboard sheet materials 1 of this embodiment are used as cardboard girders 103. This cardboard pallet P is made up of a cardboard deck board D that serves as a loading surface, and a plurality of cardboard girders 103 that support this cardboard deck board D. This cardboard deck board D is made by stacking a plurality of sheets of cardboard.

[0065] In this embodiment, the cardboard girder 103 has a height of 60 mm, a width of 130 mm, and a length of 1100 mm. A typical girder size is 90 mm in height and width, but it can also be made to these sizes.

[0066] When used as the cardboard girder 103 in this embodiment, since one can put a hand into the opening O, when moving the cardboard pallet P by hand, for example, one can insert a finger into the opening O of the cardboard girder 103 and also hook a finger on the cardboard deck board D and move both of them while holding.

[0067] Note that the cardboard pallet P in this embodiment is a double-sided offset pallet with the cardboard deck board D serving as the loading surface being located above and below, but it may also be a single-sided offset pallet. Also, by using the short cardboard girder 103, it may be a four-sided offset pallet.

[0068] As described above, the cardboard sheet material 1 of this embodiment becomes the square tube-shaped member 100 by winding while bending from the internal structure sheet portion 10 toward the exterior sheet portion 50. Thus, it has sufficient strength, good workability, and a short assembly time.

[0069] Note that the cardboard sheet material 1 of this embodiment has cuts along the winding direction R provided also between the first fold line 11 and the second fold line 12 (between the third fold line 13 and the fourth fold line 14), which are the right-inclined cuts 20 inclined to the right direction and the left-inclined cuts 21 inclined to the left direction. However, the cuts do not necessarily have to be inclined, and cuts parallel to the winding direction can also be adopted.

[0070] Also, the cardboard sheet material 1 of this embodiment has a rectangular opening shape as shown in FIG. 1B. This opening shape can also be changed by the amount of deviation downstream between the positions of the first fold line 11 and the second fold line 12 between the first fold line 11 and the second fold line 12. For example, if the amount of deviation is small, the height of the opening becomes high. Also, thereby it becomes stronger against the load from the vertical direction. On the other hand, if the amount of deviation becomes large, the height of the opening becomes low, and thereby it becomes stronger against the load from the horizontal direction.

[0071] In addition, the outer packaging sheet portion 50 of the cardboard sheet material 1 of the present embodiment formed four outer surfaces 61 to 64, namely the first to fourth outer surfaces. However, the number of outer surfaces is not limited to four. It is also possible to increase the number of packaging folds to form more outer surfaces, or to reduce the number of packaging folds to have fewer outer surfaces.

Explanation of Reference Numerals

[0072] 1: Cardboard sheet material 100: Square tube-shaped member 10: Internal structure sheet portion 11, 11u, 11d: First fold 12, 12u, 12d: Second fold 13, 13u, 13d: Third fold 14, 14u, 14d: Fourth fold 20: Right inclined cut 21: Left inclined cut 30: Structure 50: Outer packaging sheet portion 51: First packaging fold 52: Second packaging fold 53: Third packaging fold 54: Fourth packaging fold 61: First outer surface 62: Second outer surface 63: Third outer surface 64: Fourth outer surface V: Virtual straight line R: Winding direction (direction of the paper width) C: Cardboard P: Cardboard pallet

Claims

1. A corrugated internal structure sheet part forming a cylindrical structure, A corrugated exterior sheet part that continues from the internal structure sheet part and wraps the structure, Consisting of, A corrugated sheet material that forms a square tube shape by winding from the side of the internal structure sheet part to the side of the exterior sheet part, The internal structure sheet part, Has four first to fourth creases extending in a direction perpendicular to the winding direction. The four first to fourth creases are the first crease, the second crease, the third crease, and the fourth crease from the upstream side which is the starting side of winding. A plurality of cuts along the winding direction are provided between the first crease and the second crease. With the cut as a boundary, the positions of the first crease and the second crease are shifted downstream between the first crease and the second crease. The first crease and the fourth crease are provided symmetrically with respect to a straight line connecting the midpoints of the second crease and the third crease. The second crease and the third crease are provided symmetrically with respect to a straight line connecting the midpoints of the second crease and the third crease. The exterior sheet part, In order to wrap the structure composed of the internal structure sheet part, it has a plurality of packaging creases extending in a direction perpendicular to the winding direction. A corrugated sheet material characterized by this.

2. The plurality of cuts along the winding direction, With respect to the winding direction, a right-inclined cut inclined to the right and a left-inclined cut inclined to the left are alternately provided. Due to the alternately provided right-inclined cut and left-inclined cut, the first crease and the second crease that are shifted with the cut as a boundary, Among the first crease and the second crease located upstream, the first crease is longer than the second crease. Among the first crease and the second crease located downstream, the first crease is shorter than the second crease. The corrugated sheet material according to Claim 1, characterized by this.

3. The exterior sheet part, A first exterior surface covering between the first crease and the second crease, A second exterior surface covering between the second crease and the third crease, A third exterior surface covering between the third crease and the fourth crease, A fourth exterior surface covering between the fourth crease and the first crease, The corrugated sheet material according to Claim 1, characterized by consisting of this.

4. A corrugated spacer characterized by consisting of the corrugated sheet material according to Claim 1.

5. A cardboard pallet comprising a cardboard deck board serving as a loading surface and a plurality of cardboard girders supporting the cardboard deck board, A cardboard pallet characterized by using the cardboard sheet material according to claim 1 as the cardboard girders.

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