Palette

Abstract

To provide a hollow structure capable of preventing easily damage of an installation object, even when installing the installation object on the surface of a tabular hollow structure; and to provide a production method of the hollow structure.SOLUTION: A recess 30, which is a recess 30 formed on the surface 50a of a tabular hollow structure 50, has a side face 31a formed by a notch 31 in the thickness direction of the hollow structure 50.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a hollow structure having a hollow structure inside. A pallet provided with

Background Art

[0002] Conventionally, a hollow structure having a hollow structure inside has been known. This hollow structure is lightweight and excellent in strength, and is used for various applications by utilizing its characteristics. As an example of various applications, it is known to attach legs to the lower surface of a hollow structure formed in a rectangular plate shape and use it as a pallet for carrying goods (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The pallet described in Patent Document 1 has a configuration in which a plurality of legs are fixed to the lower surface of a hollow structure, and the upper surface of the hollow structure is used as a loading surface for goods. By the way, the surface of the hollow structure is formed smoothly and flatly, and has a lower coefficient of friction than, for example, wood. For this reason, it is conceivable to attach an anti-slip rubber sheet or the like to the upper surface of the pallet for the purpose of preventing the goods placed on the pallet from moving.

[0005] However, as described above, the surface of the hollow structure is formed smoothly and flatly. When a rubber sheet is attached to the upper surface of the pallet, the rubber sheet protrudes from the upper surface of the pallet by its height (thickness). In such a configuration, it is conceivable that the rubber sheet is peeled off from the upper surface of the pallet when the goods hit the pallet when loading the goods.

[0006] ​Similarly, this can also occur when installing a member on the surface of a hollow structure, not limited to a non-slip rubber sheet, or when forming a printed layer on the surface of the hollow structure. Hereinafter, other components installed on the surface of the hollow structure by fixing, forming, etc. are referred to as "installed objects". Since the installed object is located exposed on the flat surface of the hollow structure, there is a problem that it is likely to come into contact with the surrounding components and is easily damaged.

[0007] Therefore, even when an installed object is installed on the surface of a plate-shaped hollow structure, the present invention makes it easy to prevent damage to the installed object. Pallet and provides it.

Means for Solving the Problems

[0008] In order to solve the above problems, claim 1 is a recess formed on the surface of a plate-shaped hollow structure, wherein the recess has a side surface formed by a cut in the thickness direction of the hollow structure.

[0009] Claim 2 is characterized in that the hollow structure is composed of a core layer and skin layers disposed on both sides thereof, and the cut is at least deeper than the thickness of the skin layer. Claim 3 is characterized in that an installed object is installed in the recess, and a side portion of the installed object is arranged in contact with the side surface of the recess.

[0010] Claim 4 is characterized in that an installed object is installed in the recess, and a side portion of the installed object is arranged spaced apart from the side surface of the recess. Claim 5 is characterized in that an installed object is installed in the recess, and the installed object is arranged in contact with the back surface of the skin layer located on the opening side of the recess.

[0011] Claim 6 is characterized in that the side portion of the installed object is located opposite to the skin layer located on the opening side of the recess in a state where the installed object is fixed to the recess. Claim 7 is characterized in that a notch is formed in the surface of the plate-shaped hollow structure in the thickness direction, and one side sandwiching the notch is pressed to form a recess.

Advantages of the Invention

[0012] According to the present invention, even when an object is installed on the surface of the hollow structure, it is possible to easily suppress damage to the object.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0014] Hereinafter, an embodiment of a pallet 10 for carrying luggage embodying the present invention (hereinafter simply referred to as "pallet 10") will be described with reference to Figs. 1 to 5. FIG. 1 is a perspective view of the pallet 10, and the pallet 10 is composed of a pallet body 20 having a rectangular shape in plan view and a plurality of legs 21 fixed to the pallet body 20. In the pallet 10, the upper surface of the pallet body 20 serves as a loading surface for the goods, and the lower surface of the pallet body 20 serves as a fixing surface for the legs 21. Further, FIG. 1 shows the width (direction), length (direction), and height / thickness (direction) of the pallet 10.

[0015] FIG. 2(a) shows a schematic cross-sectional view of the pallet 10. The pallet body 20 is composed of a hollow structure 50 in which two concave portions 30 (see FIG. 2(b)) extending in the length direction are formed in parallel on the upper surface, and rubber sheets 40 for anti-slip as installation objects respectively installed in the concave portions 30. Note that the installation object is not limited to a member having a certain thickness such as a rubber sheet, but is a concept including those with a thin thickness such as a printed layer and a seal. Further, installation means being positioned on the surface of the hollow structure, and includes concepts such as the formation of a printed layer, the attachment of a seal, the attachment by an adhesive, the attachment by screws / nails, etc., and the attachment using a fitting structure.

[0016] The concave portion 30 is a thin portion of the thickness of the hollow structure 50. The rubber sheet 40 is arranged in the concave portion 30 and its upper end protrudes from the pallet body 20 to prevent the goods placed on the upper surface of the pallet body from slipping.

[0017] FIG. 2(b) shows a schematic cross-sectional view centered on the concave portion 30 of the hollow structure 50 constituting the pallet body 20. The upper surface and the lower surface of the pallet body 20 respectively correspond to the upper surface 50a and the lower surface 50b of the hollow structure 50.

[0018] The upper surface 50a of the hollow structure 50 is formed flat and smooth except for the concave portion 30. Also, the lower surface 50b of the hollow structure 50 is formed flat and smooth. Note that the surface refers to the upper surface 50a and the lower surface 50b of the plate-shaped hollow structure 50.

[0019] The hollow structure 50 has a configuration in which a hollow core layer 51 and skin layers 52 and 53 are disposed and integrated on both sides of the same core layer 51, respectively. As an example, the hollow structure 50 has a width of 110 cm, a length of 100 cm, and a height (thickness) of 3 cm for the portion that is not the recess 30. Therefore, the pallet body 20 is also substantially the same in terms of width, length, and height. In FIGS. 2(a) and 2(b), the sizes of the recess 30 and the rubber sheet 40 with respect to the hollow structure 50 are shown enlarged for greater emphasis.

[0020] FIG. 3(a) shows a cross-sectional perspective view of the hollow structure 50 before the formation of the recess. As shown in the figure, the hollow structure 50 has a hollow plate shape as a whole with a plurality of column-shaped cells S arranged in parallel inside. FIG. 3(b) shows a cross-sectional view taken along the line α-α of FIG. 3(a), and FIG. 3(c) shows a cross-sectional view taken along the line β-β of FIG. 3(a). As shown in FIGS. 3(b) and 3(c), the hollow structure 50 is composed of a core layer 51 with a plurality of column-shaped cells S arranged in parallel inside, and sheet-like skin layers 52 and 53 joined to the upper and lower surfaces thereof. The core layer 51 is formed by folding a single sheet material made of a thermoplastic resin formed into a predetermined shape. And the core layer 51 is composed of an upper wall portion 54, a lower wall portion 55, and side wall portions 56 erected between the upper wall portion 54 and the lower wall portion 55 to partition the cells S into a hexagonal prism shape.

[0021] As shown in FIGS. 3(b) and 3(c), in the cell S partitioned inside the core layer 51, there are a first cell S1 and a second cell S2 with different configurations. As shown in FIG. 3(b), in the first cell S1, an upper wall portion 54 with a two-layer structure is provided at the upper part of the side wall portion 56. Each layer of this upper wall portion 54 with a two-layer structure is joined to each other. Also, in the first cell S1, a lower wall portion 55 with a single-layer structure is provided at the lower part of the side wall portion 56. On the other hand, as shown in FIG. 3(c), in the second cell S2, an upper wall portion 54 with a single-layer structure is provided at the upper part of the side wall portion 56. Also, in the second cell S2, a lower wall portion 55 with a two-layer structure is provided at the lower part of the side wall portion 56. Each layer of this lower wall portion 55 with a two-layer structure is joined to each other. Further, as shown in FIGS. 3(b) and 3(c), between adjacent first cells S1 and between adjacent second cells S2, they are partitioned by side wall portions 56 with a two-layer structure respectively. This side wall portion 56 with a two-layer structure has a portion that is not thermally welded to each other at the central part in the thickness direction of the core layer 51. Therefore, the internal space of each cell S in the core layer 51 communicates with the internal space of other cells S through the space between the side wall portions 56 with a two-layer structure.

[0022] As shown in FIG. 3(a), the first cells S1 are arranged side by side in a row along the X direction. Similarly, the second cells S2 are arranged side by side in a row along the X direction. The rows of the first cells S1 and the rows of the second cells S2 are alternately arranged in the Y direction orthogonal to the X direction. And by these first cells S1 and second cells S2, the core layer 51 forms a honeycomb structure as a whole.

[0023] As such a hollow structure 50, there is the product name TEXEL (registered trademark) series of Gifu Plastic Industry Co., Ltd. As shown in Fig. 2(b), the recess 30 is composed of a pair of cuts 31, 31 and a bottom surface 32 positioned between the pair of cuts 31, 31. The pair of cuts 31, 31 are formed orthogonally from the upper surface 50a of the hollow structure 50 to a predetermined depth of the hollow structure 50. The bottom surface 32 is positioned between the pair of cuts 31, 31 and is at a lower position in the height direction than the upper surface 50a of the pallet body 20 on both outer sides of the pair of cuts 31, 31.

[0024] The pair of cuts 31, 31 constituting the recess 30 and the bottom surface 32 positioned therebetween are formed over the entire length direction of the hollow structure 50, and both ends in the length direction of the recess 30 communicate with both end faces in the length direction of the hollow structure 50. As an example, the width of the pair of cuts 31, 31 is 1 cm, and the depth of the bottom surface 32 is 1 cm based on the upper surface 50a of the hollow structure 50.

[0025] That is, the recess 30 of the hollow structure 50 is composed of a pair of cuts 31, 31, more specifically, both side surfaces 31a, 31a extending in the height direction formed by the cuts 31, 31, and a bottom surface 32 positioned between the both side surfaces 31a, 31a. The side surface 31a is composed of the core layer 51 and the skin layer 52 of the hollow structure 50, and the bottom surface 32 is composed of the skin layer 52 of the hollow structure 50. Also, the lower ends of the pair of cuts 31, 31 constituting the recess 30 are formed deeper than the bottom surface 32. For this reason, the side edges in the width direction of the bottom surface 32 are not connected to the both side surfaces 31a, 31a.

[0026] The depth of the cuts 31, 31 is twice the depth of the recess 30 based on the upper surface 50a of the hollow structure 50. Specifically, when the depth of the bottom surface 32 from the upper surface 50a is 1 cm, the depth of the cuts 31, 31 from the upper surface 50a is 2 cm.

[0027] As shown in Fig. 2(a), in the pallet body 20, a long rubber sheet 40 serving as an anti-slip member is fixed in the recess 30. The bottom of this rubber sheet 40 has the same width of 1 cm as the recess 30, and the height is 1.3 cm, which is slightly higher than the depth of the recess 30. The rubber sheet 40 has a rectangular shape in the cross-section shown in Fig. 2(a). The rubber sheet 40 is fixed in the recess 30 with its side and bottom surfaces in contact with the side surface 31a and the bottom surface 32 of the recess 30, respectively. Also, since the height of the rubber sheet 40 is slightly higher than the depth of the recess 30, the side portion of the rubber sheet 40 is in contact with the upper end of the skin layer 52 that constitutes the upper surface 50a of the hollow structure 50.

[0028] Each of the legs 21 has a substantially quadrangular prism shape, and a total of 9 pieces are arranged in 3 rows each in the width direction and the length direction with respect to the lower surface of the pallet body 20 in a substantially uniform manner and are fixed by heat fusion. Specifically, the legs 21 disclosed in JP-A-2018-43356 can be used.

[0029] Manufacturing method of the pallet 10 Next, the manufacturing method of the pallet 10 will be described. As a procedure, first, the hollow structure 50 is manufactured. Next, a recess 30 is formed in the upper surface 50a of the hollow structure 50, and the rubber sheet 40 is fixed in the recess 30 to obtain the pallet body 20. Finally, the legs 21 are fixed to the pallet body 20.

[0030] Manufacturing method of the hollow structure 50 As shown in Fig. 4(a), the first sheet material 100 is formed by molding a single sheet of thermoplastic resin into a predetermined shape. In the first sheet material 100, strip-shaped planar regions 110 and bulging regions 120 are alternately arranged in the longitudinal direction (X direction) of the first sheet material 100. In the bulging region 120, a first bulging portion 121 having a downward groove-shaped cross section formed by an upper surface and a pair of side surfaces is formed over the entire extending direction (Y direction) of the bulging region 120. It is preferable that the angle formed by the upper surface and the side surface of the first bulging portion 121 is 90 degrees. As a result, the cross-sectional shape of the first bulging portion 121 is a downward U shape. Also, the width of the first bulging portion 121 (the length in the short direction of the upper surface) is set to be equal to the width of the planar region 110 and to be twice the bulging height of the first bulging portion 121 (the length in the short direction of the side surface).

[0031] Further, in the bulging region 120, a plurality of second bulging portions 122 having a trapezoidal shape obtained by bisecting a regular hexagon with its longest diagonal line are formed so as to be orthogonal to the first bulging portion 121. The bulging height of the second bulging portion 122 is set to be equal to the bulging height of the first bulging portion 121. Also, the interval between adjacent second bulging portions 122 is equal to the width of the upper surface of the second bulging portion 122.

[0032] These first bulging portions 121 and second bulging portions 122 are formed by partially bulging the sheet upward using the plasticity of the sheet. Also, the first sheet material 100 can be formed from a single sheet by a well-known molding method such as a vacuum molding method or a compression molding method.

[0033] As shown in FIGS. 4(a) and 4(b), the core layer 51 is formed by folding the first sheet material 100 along the boundary lines P and Q. Specifically, the first sheet material 100 is valley-folded at the boundary line P between the planar region 110 and the bulging region 120, and is mountain-folded and compressed in the X direction at the boundary line Q between the upper surface and the side surface of the first bulging portion 121. Then, as shown in FIGS. 4(b) and 4(c), the upper surface and the side surface of the first bulging portion 121 are folded over each other, and the end surface of the second bulging portion 122 and the planar region 110 are folded over each other. As a result, a prismatic partition body 130 extending in one Y direction is formed for one bulging region 120. By continuously forming such partition bodies 130 in the X direction, a hollow plate-shaped core layer 51 is formed.

[0034] When the first sheet material 100 is compressed as described above, the upper wall portion 54 of the core layer 51 is formed by the upper surface and the side surface of the first bulging portion 121, and the lower wall portion 55 of the core layer 51 is formed by the end surface of the second bulging portion 122 and the planar region 110. As shown in FIG. 4(c), the portion where the upper surface and the side surface of the first bulging portion 121 in the upper wall portion 54 are folded over each other to form a two-layer structure is the overlapping portion 131. Also, the portion where the end surface of the second bulging portion 122 and the planar region 110 in the lower wall portion 55 are folded over each other to form a two-layer structure is also the overlapping portion 131.

[0035] Further, the hexagonal prism-shaped region where the second bulging portion 122 is folded and partitioned becomes the second cell S2, and the hexagonal prism-shaped region partitioned between a pair of adjacent partition bodies 130 becomes the first cell S1. In the present embodiment, the upper surface and the side surface of the second bulging portion 122 constitute the side wall portion 56 of the second cell S2, and the side surface of the second bulging portion 122 and the planar portion located between the second bulging portions 122 in the bulging region 120 constitute the side wall portion 56 of the first cell S1. Then, the contact portions between the upper surfaces of the second bulging portions 122 and the contact portions between the planar portions in the bulging region 120 form the side wall portion 56 having a two-layer structure. In performing such a folding process, it is preferable to heat-treat the first sheet material 100 to make it in a softened state.

[0036] On the upper and lower surfaces of the core layer 51 thus obtained, second sheet materials made of a thermoplastic resin are joined by heat welding, respectively. The second sheet material joined to the upper surface of the core layer 51 becomes the skin layer 52, and the second sheet material joined to the lower surface of the core layer 51 becomes the skin layer 53.

[0037] When the second sheet materials (skin layers 52 and 53) are heat-welded to the core layer 51, the upper wall portions 54 (overlapping portions 131) of the two-layer structure in the first cell S1 are heat-welded to each other. Similarly, the lower wall portions 55 (overlapping portions 131) of the two-layer structure in the second cell S2 are heat-welded to each other. On the other hand, heat is less likely to be transmitted to the side wall portions 56 of the two-layer structure in the first cell S1 and the second cell S2 compared to the upper wall portions 54 and the lower wall portions 55. Therefore, there are portions that are not joined to each other by heat welding between the side wall portions 56 of the two-layer structure. As a result, the internal spaces of the respective cells S are not completely closed spaces, and the internal spaces of the respective cells S communicate with each other through the spaces between the side wall portions 56 of the two-layer structure that are not joined by heat welding.

[0038] The long hollow structure 50 manufactured in this way is cut to a predetermined size (width 110 cm, length 100 cm), and then the process of forming the recess 30 is carried out. Formation of the recess 30 As shown in FIG. 5(a), first, a cut 31 with a depth of 2 cm in the height direction is made across the entire length of the hollow structure 50 from the upper surface 50a of the plate-shaped hollow structure 50 to the position where the side surface 31a of the recess 30 is formed. There are two linear recesses 30 in the pallet body 20 of the present embodiment, and side surfaces 31a are provided on both sides of each recess 30 (see FIG. 2(a)). Therefore, two pairs of four parallel cuts 31 are made in the hollow structure 50. The widths of the paired cuts 31 and 31 are the same as the width of the recess 30, which is 1 cm.

[0039] For forming the notch 31, a known half-cutting device may be used. For example, if there are four downward blades corresponding to the total length of the notch 31, that is, the length corresponding to the length of the hollow structure 50, four notches can be formed in the hollow structure 50 simultaneously in one operation. Also, after forming one notch 31 in the hollow structure 50 using one downward blade, the notch 31 may be sequentially formed while relatively moving the downward blade and the hollow structure 50 in the width direction, and a total of four notches 31 may be formed. Alternatively, a method may be used in which the lateral blade is fixed at a certain height from the base and the blade is relatively moved in the length direction of the hollow structure 50 to form the notch 31.

[0040] By the notching operation, four notches 31 with a depth of 2 cm that penetrate the skin layer 52 and reach the core layer 51 are formed on the upper surface 50a of the hollow structure 50. Note that in FIG. 5, the depth of the notch 31 is emphasized with respect to the thickness of the hollow structure 50.

[0041] As shown in FIG. 5(b), subsequently, hot pressing is performed between the paired notches 31, 31 from the upper surface 50a of the hollow structure 50. The hot press has a rectangular hot press device 60 having a width corresponding to the width of the paired notches 31, 31 and a length corresponding to the length of the hollow structure 50, and this is pressed from the upper surface 50a of the hollow structure 50 at a predetermined pressure in a state heated to a predetermined temperature, for example, 70 to 100 degrees. Also, the press depth is set to the same 2 cm as the depth of the notch 31.

[0042] By the hot press device 60, the hollow structure 50 between the paired notches 31, 31 is compressed in a form where it is crushed from above, but since the notches 31, 31 are formed on both sides at the press location, only the hollow structure 50 located between the pair of notches 31, 31 can be pressed.

[0043] After that, when the press is released, the hollow structure 50 at the press part returns a certain amount of thickness by its own elastic force, but the return height is about 1 / 2 of the pressing amount by the press under the conditions of this embodiment, that is, 1 cm.

[0044] As shown in Fig. 5(c), after pressing, two recesses 30 with a depth of 1 cm and a width of 10 cm are formed in the hollow structure 50. The recesses 30 formed by pressing are in the following state.

[0045] The side wall 56 of the cell S in the core layer 51 constituting the hollow structure 50 (see Fig. 3) is bent to the depth of the notch 31 and crushed, or cracks are generated in the side wall 56, or the side wall 56 is broken to form holes, and these states are mixed. Also, the side wall 56 of the cell S located further below the notch 31 is also bent and crushed, or cracks are generated in the side wall 56, or the side wall 56 is broken to form holes, and these states are mixed.

[0046] Furthermore, the bending, cracking, and breaking of the side wall 56 of the cell S occur more frequently in the part of the lower skin layer 53 among the two skin layers 52 and 53 on both sides, and more frequently in the side wall 56 near the center than near the two skin layers 52 and 53 on both sides.

[0047] And the bending, cracking, and breaking of the side wall 56 of the cell S are mostly formed between the notches 31, 31, but are also formed outside the notches 31, 31. Attachment of the rubber sheet 40 Subsequently, the rubber sheet 40 is fixed to the recess 30 of the hollow structure 50 with an adhesive. The rubber sheet 40 is formed in a long shape by a known method, for example, extrusion molding, and is cut to match the length of the pallet body 20 and used. Note that since the width of the rubber sheet 40 is the same as that of the recess 30 and the height of the rubber sheet 40 is slightly higher than the height of the recess, the rubber sheet 40 can be fixed on the bottom surface 32 and both side surfaces 31a of the recess 30 by applying the adhesive to the bottom and both sides of the rubber sheet 40.

[0048] Also, as shown in Fig. 2(a), the rubber sheet 40 is slightly higher than the height of the side surface 31a of the recess 30. The side portion of the rubber sheet 40 is positioned to face the skin layer 52 of the side surface 31a which is the opening end of the recess 30. Therefore, the recess 30 is blocked by the rubber sheet 40 and the skin layer 52, and it is difficult for dust and the like to enter the cells S1 and S2 of the core layer 51 from the notch 31. Thus, the pallet body 20 is completed.

[0049] Attachment of the legs 21 The legs 21 prepared in advance are fixed to the lower surface 50b of the pallet body 20 by heat fusion respectively. Thus, the pallet 10 of the present embodiment shown in Fig. 1 is completed.

[0050] According to the pallet 10 of the above embodiment, the following effects can be obtained. (1) In the above embodiment, the pair of notches 31, 31 are formed on the upper surface 50a (surface) of the hollow structure 50, and the recess 30 has a bottom surface 32 lower than the upper surface 50a located outside both notches 31, 31 between the pair of notches 31, 31. Therefore, even if the anti-slip rubber sheet 40 is installed in the recess 30, the height of the rubber sheet 40 can be offset by the depth of the recess 30. And the protrusion of the rubber sheet 40 from the upper surface 50a can be reduced, and the damage of the rubber sheet 40 is easily suppressed.

[0051] (2) The recess 30 is formed by forming a pair of notches 31, 31 with a certain depth from the upper surface 50a of the hollow structure 50, and then thermally pressing the hollow structure 50 between the notches 31, 31. Since the hollow structure 50 is separated into a pressed portion and a non-pressed portion with the notch 31 in between, the cells S1, S2 of the non-pressed hollow structure 50 are less affected by the pressing.

[0052] (3) The notch 31 is formed deeper than the recess 30 to be formed in consideration of the shape recovery due to the elasticity of the hollow structure 50 after thermal pressing. Therefore, the hollow structure 50 can be pressed deeper (twice in this embodiment).

[0053] (4) The notch 31 cuts a part of one skin layer 52 and the core layer 51 of the hollow structure 50. However, since the depth (2 cm) of the notch 31 with respect to the overall thickness (10 cm) of the hollow structure 50 is small, the strength of the hollow structure 50 is not likely to decrease.

[0054] (5) A rubber sheet 40 having a width corresponding to the width of the recess 30 is disposed in the recess 30. For this reason, both side portions of the rubber sheet 40 are in contact with the side surface 31a of the recess 30, and it is difficult for dust or the like to enter therebetween. (6) The height of the rubber sheet 40 is made higher than the side surface 31a of the recess 30. For this reason, the side portion of the rubber sheet 40 is positioned to face the skin layer 52 of the side surface 31a on the opening side of the recess 30, and it is difficult for dust or the like to enter the cells S1 and S2 of the core layer 51 from the notch 31.

[0055] Note that the above embodiment may be modified as follows. ○ The side surface 31a of the recess 30, that is, the notch 31, is formed in a shape perpendicular to the upper surface 50a of the hollow structure 50 constituting the pallet body 20, but it may be in an oblique direction with respect to the upper surface 50a.

[0056] ○ The depth of the notch 31 and the depth of the press can be changed according to the structure and material of the hollow structure 50, etc. For example, even when forming recesses 30 of the same depth, the depth of the notch 31 and the depth of the press can be made different in accordance with the difference in the shape recovery amount after hot pressing due to the difference in the shape and material of the hollow structure 50.

[0057] ○ The depth of the notch 31 may be made to reach in front of the skin layer 53 located below the hollow structure 50 (almost cutting the core layer 51), or may be made to reach a part of the skin layer 53 located below the hollow structure 50 (completely cutting the core layer 51 and the skin layer 52).

[0058] ○ Not limited to hot pressing, the recess 30 may be formed by a press without heating. For example, the hollow structure 50 may be heated to a softened state, and the recess 30 may be formed by a press without heating.

[0059] ○ The depth of the recess 30 is not particularly limited and may be 1 / 3, 1 / 2, or 2 / 3 of the thickness of the hollow structure 50. ○ The depth of the recess 30 may be the same as or deeper than the depth of the notch 31.

[0060] ○ Although both ends in the length direction of the notch 31 and the recess 30 communicate with the end portions in the length direction of the hollow structure 50, one or both of the length directions of the notch 31 and / or the recess 30 may not communicate with the end portions in the length direction of the hollow structure 50. In this case, there are no notches at both tips (the short sides of the recess 30), and the portion between the recess 30 and the upper surface 50a is an inclined surface.

[0061] ○ Although two parallel recesses 30 are formed, the shape is not limited to this. For example, one or three or more recesses 30 may be provided, or they may be non-parallel in the case of a plurality, or the recess 30 may be cross-shaped in plan view. In this case, the notch 31 and the press are shaped according to the shape of the recess 30 in plan view.

[0062] ○ Although the shape of the recess 30 is rectangular in plan view, a curved shape, circular shape, or the like may also be adopted. In this case, the notch 31 and the press formed in the hollow structure 50 are curved or circular.

[0063] ○ The fixing of the rubber sheet 40, which is the installation object, to the recess 30 may be, for example, by pasting using double-sided tape and is not particularly limited. ○ When installing the installation object in the recess 30, the side surface 31a of the recess 30 and the installation object may be spaced apart so as not to come into contact with each other.

[0064] ○ When installing the installation object in the recess 30, the upper surface of the installation object may be arranged to contact the back surface of the skin layer 52 located on the opening side of the recess 30. According to this arrangement, the upper surface of the installation object is suppressed from above by the skin layer 52, and the installation object is less likely to come off from the recess 30.

[0065] ○ As shown in Fig. 6(a), the recess 30 may be formed so as to be located at both ends in the width direction of the hollow structure 50. In this case, one cut 31 that constitutes the side surface 31a of the recess 30 located at both ends is sufficient.

[0066] ○ As shown in Fig. 6(b), the plate-like hollow structure 50 may be used as a floor material laid on the floor. In this case, the recess 30 is formed on the lower surface 50b of the hollow structure 50, and a non-slip rubber sheet 40 is installed in this recess 30. Although not shown, the recess 30 may be formed on both the upper and lower surfaces of the hollow structure 50, and non-slip devices may be installed on both surfaces, or members having other functions may be installed.

[0067] ○ The member installed in the recess 30 may be thinner than the depth of the recess 30. For example, it is conceivable to use the hollow structure 50 as a floor material for the travel of an automated guided vehicle. A non-contact IC tag 70 may be installed in the recess 30 of the hollow structure 50. Then, when other components hit the IC tag 70 installed in the recess 30, the impact is absorbed by the elasticity on the back side of the recess 30, making it difficult to be damaged. Therefore, it is possible to protect precision parts with the hollow structure 50 and at the same time grasp the position information of the automated guided vehicle with the IC tag 70. In this case, as shown in the figure, a cover may not be provided. When there is no cover, the IC tag 70 can absorb the impact by moving within the recess 30.

[0068] ○ The recess 30 can also be closed with a cover. In this case, a cover having the shape of the recess 30 can be used. Furthermore, the cover is not limited to the shape of the recess 30 and can also be arranged so as to cover the entire upper surface 50a or the lower surface 50b of the hollow structure 50 in which the recess 30 is formed.

[0069] ○ The hollow structure 50 is formed by folding a single first sheet material 100 to form a core layer 51 as a honeycomb structure in which hexagonal cells S are partitioned and formed inside the core layer 51. However, the forming method is not limited to this. For example, as described in Japanese Patent No. 4368399, a three-dimensional structure provided with a plurality of rows of convex portions having a trapezoidal cross-section may be sequentially folded to form the core layer 51 as a honeycomb structure.

[0070] ○ In the hollow structure, hexagonal columnar cells S were partitioned and formed inside the core layer 51. However, the shape of the cells S is not particularly limited and may be, for example, a polygonal shape such as a quadrangular column or an octagonal column, or a cylindrical shape. Further, the shape of the cells S may be a truncated conical shape. In that case, cells of different shapes may be mixed. Also, the cells do not have to be adjacent to each other, and there may be a gap (space) between the cells.

[0071] ○ The hollow structure 50 is not limited to one in which columnar cells S are partitioned. For example, it may be one in which a skin layer is joined to the upper surface or the lower surface of a core layer having a predetermined uneven shape such as a conical shape or a columnar shape. Examples of the hollow structure having such a configuration include those described in Japanese Unexamined Patent Application Publication No. 2014-205341. Also, it may be a plastic corrugated board having a harmonic cross-section.

[0072] ○ The object to be installed in the recess 30 is not limited to one having a thickness (height) such as the rubber sheet 40, and may be a thin one such as a printing layer, a seal, or a card holder. For example, by providing a printing layer in the recess 30, the printing layer is located deeper from the surface 50a of the hollow structure 50, contact with other components can be suppressed, and damage can be prevented.

[0073] ○ The position, member, etc. for forming the recess 30 are not limited. For example, a recess can also be formed on the side surface of a box, the side surface of a pallet box, a partition, the deck board of an automobile, etc.

[0074] Next, the technical ideas that can be grasped from the above embodiments and modified examples will be added below together with their effects. (a) A member is installed in the recess of the hollow structure, and the member is covered with a cover. The cover is flush with the surface of the hollow structure or is located inside in the height direction from the surface. Therefore, according to the invention described in (a), it is also possible to arrange precision parts in the recess of the hollow structure without exposing them.

Description of Reference Numerals

[0075] 10… Pallet 20… Pallet body 30… Recess 31… Notch 31a… Side surface 40… Rubber sheet (installed object) 50… Hollow structure 50a… Upper surface (surface) 50b… Lower surface (surface) 51… Core layer 52… Skin layer 53… Skin layer

Claims

**Claim 1**: A plate-shaped hollow structure comprising a resin core layer and resin skin layers disposed on both sides thereof, and a rubber sheet installed in a recess on the surface of the hollow structure. The recess is composed of both side surfaces extending in the height direction formed by a pair of cuts and a bottom surface located between the both side surfaces. The bottom surface is constituted by the skin layer. The lower ends of the pair of cuts are deeper than the bottom surface, and the side edges in the width direction of the bottom surface are not connected to the both side surfaces. The core layer has a plurality of cells partitioned by side wall portions arranged side by side. The side wall portions of the cells located in the recess are bent, cracked, and in a broken state. A pallet, characterized in that the height of the rubber sheet is higher than the height of the recess. **Claim 2**: A plate-shaped hollow structure comprising a resin core layer and resin skin layers disposed on both sides thereof, and a printing layer, a seal, or a card holder installed in a recess on the surface of the hollow structure. The recess is composed of both side surfaces extending in the height direction formed by a pair of cuts and a bottom surface located between the both side surfaces. The bottom surface is constituted by the skin layer. The lower ends of the pair of cuts are deeper than the bottom surface, and the side edges in the width direction of the bottom surface are not connected to the both side surfaces. The core layer has a plurality of cells partitioned by side wall portions arranged side by side. The side wall portions of the cells located in the recess are bent, cracked, and in a broken state. A pallet, characterized in that the printing layer, the seal, or the card holder installed in the recess is located deeper from the surface of the hollow structure. **Claim 3** The pallet according to claim 1, characterized in that the side portion of the rubber sheet is disposed in contact with the side surface of the recess. **Claim 4** The pallet according to claim 1, characterized in that the side portion of the rubber sheet is disposed spaced apart from the side surface of the recess. **Claim 5** The pallet according to claim 1, characterized in that the rubber sheet is disposed in contact with the back surface of the skin layer located on the opening side of the recess. **Claim 6** The pallet according to claim 3, characterized in that the side portion of the rubber sheet is located opposite to the skin layer located on the opening side of the recess in a state where the rubber sheet is fixed to the recess.

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