Pallet

Abstract

To provide a pallet which can improve flexural rigidity, particularly flexural rigidity in the vicinity of a fork insertion port, and which can be made less flexible.SOLUTION: A pallet 1 comprises an upper face deck part 2, a lower face deck part 3 and a girder part 4, and is formed into a plan view rectangular shape. The girder part 4 comprises a corner girder 41, an intermediate girder 42 and a central girder 43, and connects the upper face deck part 2 and the lower face deck part 3. The pallet 1 is formed with a fork insertion port 10 with a side view rectangular shape between the upper face deck part 2 and the lower face deck part 3 and also between the corner girder 41 and the intermediate girder 42. The upper face deck part 2 located at a corner part 101 of the fork insertion port 10 is formed with an arch rib 5 configuring the corner part 101 in such a manner that it has an arch part 50 with a side view arch shape projecting so as to locate below as it approaches one side vertical edge 104 configuring the corner part 101.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a pallet, and more particularly to a pallet that includes an upper deck portion, a lower deck portion, corner girders, intermediate girders, and a central girder, and in which fork insertion openings are formed between the upper deck portion and the lower deck portion, and between the corner girders and the intermediate girders. [Background technology]

[0002] Conventionally, there has been known a synthetic resin pallet in which a plurality of girders are arranged between an upper deck section and a lower deck section to connect the upper deck section and a fork insertion opening is formed between adjacent girders (see, for example, Patent Document 1). The fork insertion opening is rectangular in side view so that the forks of a forklift can be inserted.

[0003] The pallet, on which cargo is loaded on the upper surface of the upper deck portion, is transported in a lifted-up state with forks inserted into the fork insertion openings. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-182739 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a pallet is lifted up by inserting a fork into the fork insertion opening, the bending rigidity near the fork insertion opening is lower than the bending rigidity of the part where the fork insertion opening is not formed, so the pallet is prone to bending.

[0006] The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a pallet that can improve bending rigidity. [Means for solving the problem]

[0007] In order to solve the above problems, one embodiment of the present invention provides a pallet comprising an upper deck portion formed in a rectangular shape in a plan view, a lower deck portion formed in a rectangular shape in a plan view, and a girder portion, which is formed in a rectangular shape in a plan view. The girder portion includes corner girders, intermediate girders, and a central girder. The corner girders connect each corner of the upper deck portion to each corner of the lower deck portion. The intermediate girders connect each middle portion of each side of the upper deck portion to each middle portion of each side of the lower deck portion. The central girders connect each center portion of the upper deck portion to each center portion of the lower deck portion. The pallet is formed with fork insertion openings between the upper deck portion and the lower deck portion, and between the corner girders and the intermediate girders.

[0008] The fork insertion opening is formed in a rectangular shape in side view, having parallel upper and lower horizontal edges and a pair of parallel side vertical edges. An arch rib that forms the corner is formed on the upper deck portion located at the corner formed by one of the pair of side vertical edges of the fork insertion opening and the upper horizontal edge, and has an arch portion that is arch-shaped in side view and protrudes downward as it approaches the one side vertical edge that forms the corner. [Effects of the Invention]

[0009] In the pallet according to the present invention, the bending rigidity, particularly the bending rigidity in the vicinity of the fork insertion openings, can be improved, making the pallet less likely to bend. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a pallet according to one embodiment, seen from above. [Figure 2] FIG. 2 is a plan view of the pallet. [Figure 3] FIG. 3 is a bottom view of the pallet. [Figure 4]Fig. 4A is a side view of the long side of the pallet, Fig. 4B is an enlarged view of part B in Fig. 4A, and Fig. 4C is an enlarged view of a part of Fig. 4B. [Figure 5] Fig. 5A is a side view of the short side of the pallet, and Fig. 5B is an enlarged view of part C in Fig. 5A. [Figure 6] Fig. 6A is a perspective view of the main part of the pallet as viewed from diagonally below, and Fig. 6B is a cross-sectional view of a rib provided on an upper end rail. [Figure 7] FIG. 7 is a cross-sectional view taken along line AA in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] FIELD OF THE INVENTION The present invention relates to a pallet. The pallet according to the present invention will be described below based on an embodiment shown in the accompanying drawings.

[0012] A pallet according to one embodiment will be described with reference to Figures 1 to 7. The strength of the pallet according to this embodiment is Class B in the JIS Z0602 test.

[0013] As shown in FIG. 1, the pallet 1 includes an upper deck portion 2, a lower deck portion 3, and a girder portion 4, and is formed into a rectangular shape in a plan view. The pallet 1 is integrally molded by injection molding of synthetic resin. That is, the upper deck portion 2 and the girder portion 4 are integrally connected, and the lower deck portion 3 and the girder portion 4 are integrally connected. In this embodiment, the pallet 1 is designed to be used with the upper deck portion 2 located on the upper side and the lower deck portion 3 located on the lower side. Although the upper deck portion 2 and the lower deck portion 3 have substantially the same outer shape in a plan view, they are not formed to have the same overall shape, height, etc. In the following description, the side where the upper deck portion 2 is located will be referred to as the upper side, and the side where the lower deck portion 3 is located will be referred to as the lower side.

[0014] The upper deck section 2 is formed in a rectangular shape when viewed from above as shown in Fig. 2, and the lower deck section 3 is formed in a rectangular shape when viewed from below (in a plan view) as shown in Fig. 3. As shown in Figs. 1 to 3, the upper deck section 2 and the lower deck section 3 are both formed with square outer shapes in a plan view, and are the same shape and size, and are arranged with a gap in the vertical direction so that their outer shapes overlap in a plan view.

[0015] As shown in Figure 2, the upper deck section 2 has a girder upper section 21, an upper sash section 22, and an upper inter-sash section 23. The girder upper section 21 is located above the girder section 4. The upper deck section 2 has, as the girder upper section 21, a corner girder upper section 211, an intermediate girder upper section 212, and a central girder upper section 213.

[0016] The corner beam upper parts 211 are located at the four corners of the upper deck section 2 in plan view. The corner beam upper parts 211 are formed by connecting a rib 24 along one side of the upper deck section 2, which has a rectangular (square) shape in plan view, to a rib 25 that is perpendicular to the rib 24. The corner beam upper parts 211 are formed in a mesh shape with through-holes that penetrate vertically. As shown in Figure 1, the corner beam upper parts 211 are located above the corner beam 41, which will be described later, and are formed integrally with the corner beam 41.

[0017] The intermediate girder upper parts 212 are located at the middle of each of the four sides of the upper deck part 2. The intermediate girder upper parts 212 are formed in a mesh shape with ribs and through holes similar to the corner girder upper parts 211. The intermediate girder upper parts 212 are located above the intermediate girder 42, which will be described later, and are formed integrally with the intermediate girder 42.

[0018] The central girder upper part 213 is located in the center of the upper surface deck part 2. The central girder upper part 213 is formed in a mesh shape with ribs and through holes similar to those of the corner girder upper part 211. The central girder upper part 213 is located above the central girder 43, which will be described later, and is formed integrally with the central girder 43.

[0019] As shown in Fig. 2, the upper rail portion 22 is located between the two upper girder portions 21 and connects the two upper girder portions 21. The upper deck portion 2 has, as the upper rail portion 22, an end upper rail portion 221 and an inner upper rail portion 222.

[0020] The end upper crosspiece 221 is located between the corner beam upper part 211 and the intermediate beam upper part 212, and connects the corner beam upper part 211 and the intermediate beam upper part 212. A total of eight end upper crosspieces 221 are provided, two on each of the four sides of the upper deck part 2. The end upper crosspieces 221 are formed in a mesh shape with ribs and through-holes similar to those of the corner beam upper part 211.

[0021] The inner upper crosspiece 222 is located between the upper intermediate girder section 212 and the upper central girder section 213, and connects the upper intermediate girder section 212 and the upper central girder section 213. A total of four inner upper crosspieces 222 are provided in a cross shape at 90-degree intervals from the upper central girder section 213. The inner upper crosspiece 222 is formed in a mesh shape with ribs and through-holes similar to those of the upper corner girder section 211.

[0022] The upper inter-span portions 23 are located in the area surrounded by the upper inter-span portions 22 on all four sides, and are connected to the upper inter-span portions 22. A total of four upper inter-span portions 23 are provided. The upper inter-span portions 23 are formed in a mesh shape with ribs and through-holes similar to those of the upper corner beam portion 211.

[0023] The upper surfaces of the girder upper portion 21, the upper sash portion 22 and the upper inter-sash portion 23 of the upper deck portion 2 are located on the same plane.

[0024] As shown in Figure 3, the lower deck section 3 has a girder lower section 31 and a lower crosspiece section 32. The girder lower section 31 is located below the girder section 4. The lower deck section 3 has, as the girder lower section 31, a corner girder lower section 311, an intermediate girder lower section 312, and a central girder lower section 313.

[0025] In plan view, the corner beam lower parts 311 are located at each of the four corners of the lower deck section 3. The corner beam lower parts 311 are formed by connecting a rib 34 along one side of the lower deck section 3 in plan view with a rib 35 that is perpendicular to this. The corner beam lower parts 311 are formed in a mesh shape with through-holes that run vertically through. The corner beam lower parts 311 are located below the corner beams 41 and are formed integrally with them.

[0026] The intermediate girder lower parts 312 are located at the middle of each of the four sides of the lower deck part 3. The intermediate girder lower parts 312 are formed in a mesh shape with ribs and through holes similar to the corner girder lower parts 311. The intermediate girder lower parts 312 are located below the intermediate girder 42 and are formed integrally with the intermediate girder 42.

[0027] The central girder lower part 313 is located in the center of the lower deck part 3. The central girder lower part 313 is formed in a mesh shape with ribs and through holes similar to the corner girder lower part 311. The central girder lower part 313 is located below the central girder 43 and is formed integrally with the central girder 43.

[0028] The lower rail portion 32 is located between the two girder lower portions 31 and connects the two girder lower portions 31. The lower deck portion 3 has, as the lower rail portion 32, an end lower rail portion 321 and an inner lower rail portion 322.

[0029] The end lower crosspiece 321 is located between the corner beam lower part 311 and the intermediate beam lower part 312, and connects the corner beam lower part 311 and the intermediate beam lower part 312. A total of eight end lower crosspieces 321 are provided, two on each of the four sides of the lower deck part 3. The end lower crosspieces 321 are formed in a mesh shape with ribs and through-holes similar to those of the corner beam lower part 311.

[0030] The inner lower crosspiece 322 is located between the intermediate girder lower part 312 and the central girder lower part 313, and connects the intermediate girder lower part 312 and the central girder lower part 313. A total of four inner lower crosspieces 322 are provided in a cross shape at 90-degree intervals from the central girder lower part 313. The inner lower crosspiece 322 is formed in a mesh shape with ribs and through holes similar to those of the corner girder lower part 311.

[0031] Inter-span openings 33 are formed in the lower deck section 3 in a portion corresponding to the upper inter-span section 23 in a plan view. A total of four inter-span openings 33 are provided, located in a portion surrounded by the lower span sections 32 on all four sides. The inter-span openings 33 are formed in a roughly rectangular shape (particularly a square shape). The lower surfaces of the lower girder section 31 and the lower span sections 32 of the lower deck section 3 are located on the same plane.

[0032] As shown in Figure 1, the girder section 4 is located between the upper deck section 2 and the lower deck section 3, and connects the upper deck section 2 and the lower deck section 3. The pallet 1 has corner girders 41, intermediate girders 42, and a central girder 43 as the girder section 4.

[0033] The corner girders 41 connect each corner of the upper deck section 2 to each corner of the lower deck section 3. Specifically, the upper corner girder 211 of the upper deck section 2 is connected to the lower corner girder 311 of the lower deck section 3, which is located below the upper corner girder 211, by a corner girder 41. A total of four corner girders 41 are provided. The girder sections 4 (corner girders 41, intermediate girders 42, and central girders 43) have tubular sections 40 that extend in the vertical direction. The horizontal cross section of the tubular sections 40 is generally rectangular (particularly oblong). Furthermore, a rib (not shown) is formed within the tubular section 40 of the corner girder 41, along one side of the upper deck section 2 in plan view, and a rib (not shown) that is connected perpendicular to this is formed within the tubular section 40.

[0034] As shown in Figure 3, inclined ribs 36 are formed at the corners of the lower deck portion 3. The inclined ribs 36 are formed inside the tubular portion 40 of the corner beam 41. By forming such inclined ribs 36, even if an object collides with the side of the corner of the pallet 1, bending stress rather than compressive force is likely to be applied to the inclined ribs 36, and the inclined ribs 36 will bend, making it easier to absorb the impact.

[0035] As shown in FIG. 2, in a plan view, the length of the corner beam 41 in the direction along the long side of the pallet 1 (see L11 in FIG. 2) is longer than the length of the corner beam 41 in the direction along the short side of the pallet 1 (see L21 in FIG. 2). The length L11 is the length of the corner beam 41 in the longitudinal direction in a plan view, and the length L21 is the length of the corner beam 41 in the short direction in a plan view. In this embodiment, the length L21 is half or less of the length L11, but the relationship between the lengths L11 and L21 is not particularly limited.

[0036] The corner beam 41 has a height H1 (see FIGS. 4B and 5B). The length L21 of the corner beam 41 in the short side direction is shorter than the height H1 of the corner beam 41.

[0037] The intermediate girders 42 connect the middle parts of each side of the upper deck section 2 to the middle parts of each side of the lower deck section 3. Specifically, the intermediate girders 42 connect the upper intermediate girder parts 212 of the upper deck section 2 to the lower intermediate girder parts 312 of the lower deck section 3, which are respectively located below the upper intermediate girder parts 212. A total of four intermediate girders 42 are provided. Like the corner girders 41, the intermediate girders 42 have a tubular section 40 that extends in the vertical direction. The shape of the tubular section 40 in horizontal cross section is generally rectangular (particularly square). Furthermore, a rib (not shown) that runs along one side of the upper deck section 2 in a plan view and a rib (not shown) that is connected perpendicular to this are formed within the tubular section 40 of the intermediate girder 42.

[0038] Of the intermediate girders 42, the intermediate girders 42 arranged along the long sides of the pallet 1 have a length in a direction along the long sides of the pallet 1 in a plan view (see L12 in Figure 2) that is longer than the length of the intermediate girders 42 in a direction along the short sides of the pallet 1 (see L21 in Figure 2). In this intermediate girder 42, the length L12 is the length in the longitudinal direction in a plan view, and the length L21 is the length in the lateral direction in a plan view. The relationship between the lengths L12 and L21 is not particularly limited. The height of this intermediate girder 42 is H1 (see Figures 4B and 5B). In this intermediate girder 42, the length L21 in the lateral direction is shorter than the height H1.

[0039] Furthermore, among the intermediate girders 42, the intermediate girders 42 arranged along the short sides of the pallet 1 have a length in a direction along the long sides of the pallet 1 in a plan view (see L11 in Figure 2) that is longer than the length of the intermediate girders 42 in a direction along the short sides of the pallet 1 (see L22 in Figure 2). In this intermediate girders 42, the length L11 is the length in the longitudinal direction in a plan view, and the length L22 is the length in the lateral direction in a plan view. Note that there is no particular limitation on the relationship between the lengths L11 and L22. The height of this intermediate girders 42 is H1 (see Figures 4B and 5B). In this intermediate girders 42, the length L22 in the lateral direction is longer than the height H1.

[0040] The central girder 43 connects the center of the upper deck section 2 and the center of the lower deck section 3. Specifically, the central girder upper section 213 of the upper deck section 2 and the central girder lower section 313 of the lower deck section 3 are connected by the central girder 43. The central girder 43 has a tubular section 40 that extends in the vertical direction, similar to the corner girders 41 and intermediate girders 42. The shape of the tubular section 40 in horizontal cross section is generally rectangular (particularly square). Furthermore, a rib (not shown) that runs along one side of the upper deck section 2 in plan view and a rib (not shown) that is connected perpendicular to this are formed within the tubular section 40 of the central girder 43.

[0041] The cylindrical portions 40 of the girder portions 4 (corner girder portions 41, intermediate girder portions 42, and central girder portion 43) extend upward to be integrated with a part of the upper deck portion 2, and extend downward to be integrated with a part of the lower deck portion 3. In other words, the cylindrical portions 40 are continuous from the upper end to the lower end of the pallet 1, and the upper deck portion 2, girder portions 4, and lower deck portion 3 are integrated.

[0042] In a plan view, the length of the central beam 43 in the direction along the long side of the pallet 1 (see L12 in FIG. 2) is the same as the length of the central beam 43 in the direction along the short side of the pallet 1 (see L22 in FIG. 2). The relationship between the lengths L12 and L22 is not particularly limited. The height of the central beam 43 is H1 (see FIGS. 4B and 5B). The lengths L12 and L22 of the central beam 43 are longer than the height H1 of the central beam 43.

[0043] When the lower surfaces of the lower girder section 31 and lower rail section 32 of the lower deck section 3 are placed on a horizontal surface, the upper surfaces of the upper girder section 21, upper rail section 22 and upper inter-rail section 23 of the upper deck section 2 are positioned on the same horizontal plane. In other words, the thickness of the pallet 1 (i.e., the vertical length between the upper and lower surfaces) is formed to be constant.

[0044] As shown in Figure 4A, the pallet 1 has fork insertion openings 10. The fork insertion openings 10 are formed between the upper deck portion 2 and the lower deck portion 3, and between the corner beam 41 and the intermediate beam 42. The fork insertion openings 10 correspond to each pair of upper end crosspieces 221 and lower end crosspieces 321, and two fork insertion openings 10 are provided on each of the four sides of the pallet 1, for a total of eight.

[0045] Specifically, as shown in Figure 4B, the fork insertion opening 10 is a portion surrounded by an upper end crosspiece 221 on the upper side, a lower end crosspiece 321 on the lower side, and corner beams 41 and intermediate beams 42 on the sides. The fork insertion opening 10 is formed in a rectangular shape in a side view (viewed from the opening direction of the fork insertion opening 10) and has an upper horizontal edge 102 and a lower horizontal edge 103 that are parallel to each other, and a pair of side vertical edges 104, 104 that are also parallel to each other. The upper horizontal edge 102 is formed by the lower edge of the upper end crosspiece 221 of the upper deck portion 2. The lower horizontal edge 103 is formed by the upper edge of the lower end crosspiece 321 of the lower deck portion 3. Of the pair of side vertical edges 104, the side vertical edge 104 on the central side of the pallet 1 (left side in Figure 4B) is formed by the side edge of the intermediate beam 42, and the side vertical edge 104 on the side farther from the center of the pallet 1 (right side in Figure 4B) is formed by the side edge of the corner beam 41.

[0046] A curved surface portion 105 is formed at the corner portion 101 of the fork insertion opening 10. In a side view, the curved surface portion 105 is formed in a so-called R-shape, which is an arc-like shape that is recessed toward the center of the fork insertion opening 10. Here, the corner portion 101 refers to the portion (and its periphery) where either the upper horizontal edge 102 or the lower horizontal edge 103 contacts either of the pair of side vertical edges 104, 104. Of the four corners 101, the curved surface portion 105 is formed at three corners 101 except for the corner 101 formed by the side vertical edge 104 (the right side in FIG. 4B ) formed by the side edge of the corner beam 41 and the upper horizontal edge 102.

[0047] The fork insertion opening 10 opens to the side, and the forks 9 of a forklift truck (see the dashed lines in FIG. 4A ) are inserted into it. The fork 9 is inserted through the fork insertion opening 10 formed on one side of the pallet 1, with the tips of the fork 9 slightly protruding from the fork insertion opening 10 formed on the opposite side of the pallet 1, but the tips of the fork 9 do not necessarily have to protrude from the fork insertion opening 10. The series of spaces into which the fork 9 can be inserted constitutes the fork insertion space 11. That is, the fork insertion space 11 is made up of a series of spaces extending in order from the space between the upper end rail 221 and the lower end rail 321 (fork insertion opening 10), between the upper inter-rail portion 23 and the portion of the lower deck portion 3 corresponding to the inter-rail opening 33, between the inner upper rail 222 and the inner lower rail 322, between the upper inter-rail portion 23 and the portion of the lower deck portion 3 corresponding to the inter-rail opening 33, and between the upper end rail 221 and the lower end rail 321 (fork insertion opening 10). Two fork insertion spaces 11 are provided in parallel between one side of pallet 1 and the opposite side, and two are provided in parallel between the side adjacent to one side of pallet 1 and the opposite side, for a total of four spaces that form a cross shape in plan view. Pallet 1 is a so-called four-way access pallet.

[0048] The upper deck portion 2 of the pallet 1 has a girder upper portion 21, an upper sash portion 22, and an upper inter-sash portion 23, and no large opening is formed in the upper deck portion 2, and loads are placed on the upper surface of the upper deck portion 2. In this embodiment, an inter-sash opening 33 is formed in the lower deck portion 3, and therefore the lower deck portion 3 is on the upper side and the upper deck portion 2 is on the lower side, and it is not suitable for loading loads on the upper surface of the lower deck portion 3. In other words, the pallet 1 of this embodiment is a single-sided pallet 1.

[0049] In the case of pallet 1, forks 9 are inserted through fork insertion openings 10, and the upper deck portion 2 is supported by the forks 9. In conventional pallet 1, when the forks 9 inserted through the fork insertion openings 10 rise, the upper surfaces of the forks 9 come into uniform contact with the upper horizontal edges 102 of the fork insertion openings 10. When the forks 9 rise further, the outer portions of the cantilevered forks 9 of the pallet 1 drop due to the weight of the load placed on the top surface of the pallet 1, causing the pallet 1 to warp downward in a concave manner, which could result in the load breaking.

[0050] Therefore, to prevent cargo placed on the upper surface of the pallet 1 from breaking apart, an arch rib 5 is formed at one of the four corners 101 where the curved surface 105 is not formed. The arch rib 5 is formed on the upper deck portion 2 at a corner 101 formed by one of a pair of side vertical edges 104, 104 and an upper horizontal edge 102. In this embodiment, the arch rib 5 is formed at the corner 101 formed by the side vertical edge 104 (i.e., the side vertical edge 104 formed by the side edge of the corner beam 41) on the side farther from the center of the pallet 1 (the right side in FIG. 4B ) and the upper horizontal edge 102. This corner 101 is formed by the upper horizontal edge 102 formed by the lower edge of the upper deck portion 2, the arch rib 5, and the side vertical edge 104 formed by the side edge of the corner beam 41.

[0051] In addition, in this embodiment, the arch rib 5 is not formed at the corner 101 formed by the side vertical edge 104 (i.e., the side vertical edge 104 formed by the side end edge of the intermediate girder 42) on the central side (left side in Figure 4B) of the pallet 1 and the upper horizontal edge 102.

[0052] Although the arch ribs 5 may be formed at all corners 101, this would increase the weight of the pallet 1, so in this embodiment they are formed only at the corners 101 on the side farthest from the center of the pallet 1 (i.e., the corner beam 41 side).

[0053] The arch rib 5 is a rib that protrudes downward as it approaches one of the side vertical edges 104 that constitute this corner portion 101 (i.e., the side vertical edge 104 that is constituted by the side edge of the corner beam 41). The arch rib 5 has an arch portion 50. The arch portion 50 is an arch-shaped (arcuate) portion in side view. The arch portion 50 is located approximately at the intersection of the side vertical edge 104 (the side edge of the corner beam 41) and the upper horizontal edge 102 (the lower edge of the upper end crosspiece 221). In this embodiment, the R (radius of curvature) of the curved portion 105 and the R of the arch portion 50 are formed to be the same.

[0054] The arch rib 5 also has a straight portion 51. The straight portion 51 extends from the end (starting end) opposite the side vertical edge 104 (side edge of the corner beam 41) of the arch portion 50, inclining upward as it moves away from the side vertical edge 104 (side edge of the corner beam 41), to the portion where it intersects with the upper horizontal edge 102. The starting end of the straight portion 51 is located closer to the arch portion 50 (to the corner beam 41) than the positions of the spot ribs 52 and 53 described below. In a plan view, the length of the straight portion 51 is longer than the length of the arch portion 50. By forming the straight portion 51 to be longer in a plan view, the strength and rigidity of the pallet 1 are improved.

[0055] The arch rib 5 includes an arch portion 50 and a straight portion 51. The arch rib 5 is the portion that protrudes downward from the original shape of the fork insertion opening 10 (the portion indicated by the dashed line with reference numeral 100, which is the fork insertion opening 10 when the arch rib 5 is not formed).

[0056] As shown in FIG. 6A, the arch rib 5 is formed over the entire length of the side surface of the girder 4 (corner girder 41 in this embodiment) facing the fork insertion opening 10. More specifically, the upper end crosspiece 221 has a plurality of ribs 54-56 (three in this embodiment) in the direction of the opening of the fork insertion opening 10, and arch ribs 5 are formed on all of these ribs 54-56. In this embodiment, as shown in FIG. 6B, of the plurality of ribs 54-56 on which the arch rib 5 is formed, the outermost rib 54 has an inverted L-shaped cross section (the shape of the cross section perpendicular to the direction in which the edge of the pallet 1 extends in a plan view). The arch rib 5 may be formed only on the outermost rib 54 of the plurality of ribs 54-56.

[0057] In this embodiment, when the forks 9 inserted through the fork insertion openings 10 rise, the outer portions of the upper surfaces of the forks 9 first come into contact with the arch ribs 5. As the forks 9 continue to rise, the weight of the load placed on the fork 9 portions on both the left and right sides of the upper surface of the pallet 1 causes these portions of the pallet 1 to also drop and deform, with the lower surfaces of the straight portions 51 mainly being supported by the inner portions of the upper surfaces of the forks 9. At this time, the portion of the pallet 1 where the arch ribs 5 are formed has first come into contact with the outer portions of the upper surfaces of the forks 9 and moved upward, and a force is applied to the pallet 1 that warps it upward so that the load placed on the upper surface is less likely to break.

[0058] Furthermore, since the arch rib 5 has an arch portion 50, it easily fits to the gentle chamfered corners of the fork 9, and the fork 9 and the straight portion 51 come into contact in a state close to line contact rather than surface contact, as occurs when there is only the straight portion 51 without the arch portion 50, thereby preventing stress concentration.

[0059] Furthermore, when the forks 9 inserted through the fork insertion openings 10 rise, the weight of the load causes the pallet 1 to deform, and the lower surfaces of the straight sections 51 are supported by the inner parts of the upper surfaces of the forks 9. At this time, because the length of the straight sections 51 is longer than the length of the arch sections 50, the area of ​​the straight sections 51 supported by the upper surfaces of the forks 9 becomes larger, and the load on the pallet 1 is distributed.

[0060] Furthermore, the girder 4 that forms the side vertical edge 104 of the corner 101 where the arch rib 5 is located is a corner girder 41 that is formed so that the length L21 in the short side direction in plan view is shorter than the height H1. That is, the corner girder 41 is formed so that the length L21 in the short side direction is short, which tends to result in insufficient bending rigidity, but by forming the arch rib 5 on this corner girder 41, bending rigidity is improved.

[0061] Furthermore, the girder 4 that forms the side vertical edge 104 of the corner 101 where the arch rib 5 is located is a corner girder 41 whose short-side length L21 in plan view is less than half of its long-side length L11. That is, the corner girder 41 is formed so that its short-side length L21 is short, which tends to result in insufficient bending rigidity, but by forming the arch rib 5 on this corner girder 41, bending rigidity is improved.

[0062] The upper deck section 2 has a belt recess 26 in a part of its outer periphery in plan view that is recessed inward more than the other parts. The belt recess 26 is formed in a part that corresponds to the arch rib 5 in plan view. When the belt recess 26 is used, a belt is passed through the fork insertion opening 10 and hung on the underside of the upper deck section 2 and the belt recess 26, and the load placed on the upper surface of the upper deck section 2 is secured by the belt. At this time, the part of the pallet 1 where the belt recess 26 is formed is prone to deformation.

[0063] Therefore, spat ribs 52 extending upward toward the belt recess 26 are formed on the surface of the arch rib 5 when viewed from the opening direction of the fork insertion port 10 where the arch rib 5 is located. In this embodiment, the spat rib 52 is located at the center of the belt recess 26 in the circumferential direction of the upper surface deck portion 2 in a plan view. One spat rib 52 is formed per arch rib 5. Similar spat ribs 53 are also formed in portions of the upper surface deck portion 2 where no arch rib 5 is formed.

[0064] By forming the spot ribs 52 on the surface of the portion of the arch rib 5 that corresponds to the belt recess 26, deformation of the pallet 1 when a belt is put through the belt recess 26 is suppressed.

[0065] Furthermore, since the spat ribs 52 are positioned in the center of the belt that is placed in the belt recess 26, the spat ribs 52 can receive the force from the belt in a balanced manner.

[0066] Furthermore, since the start end of the straight portion 51 of the arch rib 5 is located closer to the arch portion 50 (toward the corner beam 41) than the positions of the spot ribs 52 and 53, there is no need to form the R that constitutes the arch portion 50 on the lower end surfaces of the spot ribs 52 and 53. This avoids difficulties in design and manufacturing.

[0067] The vertical length of the spot ribs 52 is longer than the vertical length of the spot ribs 53.

[0068] As shown in FIG. 4C, H2 denotes the difference between the height of the original shape 100 of the fork insertion opening 10 and the height of the intersection of the imaginary extension line of the straight line portion 51 and the side vertical edge 104 on the corner beam 41 side. Also, as shown in FIG. 6B, T1 denotes the width of the outermost rib 54 of the multiple ribs 54 to 56 that the end upper crosspiece 221 has. In this case, T1 and H2 are calculated by the following formula 1: (Formula 1)0.8T1 <H2<8T1 It is preferable that T1 and H2 satisfy the relationship shown below (Equation 2). (Formula 2)T1 <H2<4T1 It is more preferable that the relationship shown in the following formula (3) is satisfied. (Formula 3) 1.5T1 <H2<2T1 It is even more preferable to satisfy the relationship shown in the formula (1) to (3). If H2 is small, the improvement in strength and rigidity of the pallet 1 will be small even if the arch rib 5 is formed. Also, if H2 is large, the weight of the pallet 1 will increase. Therefore, by satisfying the relationships shown in the formulas (1) to (3) above, it is possible to suppress an increase in the weight of the pallet 1 while ensuring the improvement in strength and rigidity of the pallet 1 when the arch rib 5 is formed.

[0069] Furthermore, a horizontal rib protruding toward the rib 55 is formed at the lower end of the outermost rib 54, and the thickness (vertical length) of this horizontal rib is defined as T2. In this case, T2 and H2 are expressed by the following formula (4): (Formula 4)T2 <H2<10T2 It is preferable that T2 and H2 satisfy the relationship shown in the following (Equation 5). (Formula 5)1.2T2 <H2<5T2 It is more preferable that the relationship shown in the following formula (6) is satisfied. (Formula 6)1.5T2 <H2<2.6T2 It is even more preferable to satisfy the relationship shown in (Formula 4) to (Formula 6). If H2 is small, the improvement in strength and rigidity of the pallet 1 will be small even if the horizontal ribs of the ribs 54 are formed. Also, if H2 is large, the weight of the pallet 1 will increase. Therefore, by satisfying the relationships shown in (Formula 4) to (Formula 6) above, it is possible to suppress an increase in the weight of the pallet 1 while ensuring the improvement in strength and rigidity of the pallet 1 when the horizontal ribs of the ribs 54 are formed.

[0070] As shown in Figure 7, the ribs that make up the upper rail portion 22 are so-called I-ribs, and the ribs that make up the upper inter-rail portion 23 are so-called T-ribs. Therefore, the bending rigidity and strength of the upper rail portion 22 are weaker than the bending rigidity and strength of the upper inter-rail portion 23. As a result, even if an object collides with the side of a corner of the pallet 1, the I-ribs of the upper rail portion 22 deform and easily absorb the impact.

[0071] Next, a modification of the above-described embodiment will be described.

[0072] The pallet 1 does not have to be formed integrally with the upper deck portion 2, the lower deck portion 3 and the beam portion 4, but may be a welded pallet in which they are formed separately and then welded together.

[0073] The arch rib 5 may also be formed on the lower deck portion 3 located at the corner 101 formed by one of the pair of side vertical edges 104, 104 and the lower horizontal edge 103. This results in arch ribs 5 being formed at both the upper corner 101 and the lower corner 101. The strength of the pallet 1 is not limited to Class B in the JIS Z 0602 test.

[0074] The pallet 1 may be formed as a double-sided pallet 1. In this case, the lower deck section 3 does not have inter-span openings 33, and similar to the upper deck section 2, lower inter-span sections that are connected to the lower inter-span sections 32 are formed at the positions of the inter-span openings 33. The lower inter-span sections are formed in a mesh shape with ribs and through-holes, similar to the upper inter-span sections 23.

[0075] The upper deck section 2 and the lower deck section 3 may be formed in a square shape in a plan view. Furthermore, the upper deck section 2 and the lower deck section 3 do not have to be formed in a strict rectangular shape in a plan view.

[0076] In the lower deck section 3 of the above-described embodiment, eight lower end rails 321 are provided, two on each of the four sides, and four lower inner rails 322 are provided radially at 90-degree intervals from the lower central girder section 313. However, the four lower end rails 321 and two lower inner rails 322 located in two of the two pairs of fork insertion spaces 11 that form a cross shape may be eliminated. In this case, the pallet 1 also becomes a so-called four-way insertion pallet.

[0077] The corner beam upper part 211, the intermediate beam upper part 212, the central beam upper part 213, the end upper crosspiece 221, the inner upper crosspiece 222 and the upper inter-crosspiece part 23 may be formed in a plate shape, and the structure is not particularly limited.

[0078] The upper surfaces of the girder upper portion 21, the upper rail portion 22 and the upper inter-rail portion 23 of the upper deck portion 2 do not necessarily have to be positioned on the same plane.

[0079] The corner beam lower part 311, the intermediate beam lower part 312, the central beam lower part 313, the end lower crosspiece 321 and the inner lower crosspiece 322 may be formed in a plate shape, and the structure is not particularly limited.

[0080] The lower surfaces of the lower girder portion 31 and the lower rail portion 32 of the lower deck portion 3 do not necessarily have to be positioned on the same plane.

[0081] The shape and structure of the cylindrical portions 40 of the corner beams 41, intermediate beams 42, and central beam 43 are not particularly limited.

[0082] The girder 4 constituting the side vertical edge 104 of the corner 101 where the arch rib 5 is located may be an intermediate girder 42. In this case, the intermediate girder 42 is formed so that the length L21 of the short side in a plan view is shorter than the height H1. Alternatively, the length L21 of the intermediate girder 42 in a short side in a plan view is formed so that it is half or less of the length L11 of the long side.

[0083] The curved surface portion 105 formed at the fork insertion opening 10 may have any configuration, and the curved surface portion 105 may not be provided at the fork insertion opening 10. Furthermore, the R (radius of curvature) of the curved surface portion 105 may be formed to be larger than the R of the arch rib 5, or may be formed to be smaller than the R of the arch rib 5. In other words, the R (radius of curvature) of the curved surface portion 105 does not have to be the same as the R of the arch rib 5. The arch ribs 5 may be formed at all corners 101.

[0084] Two, three, four, or more spot ribs 52 may be formed on one arch rib 5. This further suppresses deformation of the pallet 1 when a belt is hung in the belt recesses 26.

[0085] An arch rib similar to the arch rib 5 may be formed on the end of the inner upper crosspiece 222 on the intermediate girder 42 side. This arch rib may be formed on the upper deck portion 2 (inner upper crosspiece 222) located at the corner formed by the lower end edge of the inner upper crosspiece 222 and the side vertical edge of the intermediate girder 42 on the central girder 43 side.

[0086] As is clear from the above-described embodiment and its modified examples, the pallet (1) of the first aspect comprises an upper deck portion (2) formed in a rectangular shape in a plan view, a lower deck portion (3) formed in a rectangular shape in a plan view, and a girder portion (4), which is formed in a rectangular shape in a plan view. The girder portion (4) comprises corner girders (41), intermediate girders (42), and a central girder (43). The corner girders (41) connect each corner of the upper deck portion (2) to each corner of the lower deck portion (3). The intermediate girders (42) connect each middle portion of each side of the upper deck portion (2) to each middle portion of each side of the lower deck portion (3). The central girder (43) connects the center of the upper deck portion (2) to the center of the lower deck portion (3). The pallet (1) has a fork insertion opening (10) formed between the upper deck portion (2) and the lower deck portion (3) and between the corner beam (41) and the intermediate beam (42).

[0087] The fork insertion opening (10) is formed in a rectangular shape in a side view, having an upper horizontal edge (102) and a lower horizontal edge (103) that are parallel to each other, and a pair of parallel side vertical edges (104, 104). An arch rib (5) that forms the corner (101) is formed on the upper deck portion (2) located at the corner (101) formed by one of the pair of side vertical edges (104, 104) of the fork insertion opening (10) and the upper horizontal edge (102), and has an arch portion (50) that is arch-shaped in a side view and protrudes downward as it approaches one of the side vertical edges (104) that forms the corner (101).

[0088] According to the first aspect, a part of the upper surface of the fork (9) inserted into the fork insertion opening (10) first hits the arch rib (5), making it less likely that the load placed on the upper surface of the pallet (1) will break.

[0089] The second aspect can be realized by combining it with the first aspect. In the second aspect, the girder (4) constituting one side vertical edge (104) of the corner (101) where the arch rib (5) is located is a corner girder (41) or an intermediate girder (42) formed so that the length (L21) in the short side direction in a plan view is shorter than the height (H1).

[0090] According to the second aspect, the arch rib (5) is formed on the beam portion (4) which is formed so as to have a short length (L21) and which tends to have insufficient bending rigidity, thereby improving bending rigidity.

[0091] The third aspect can be realized by combining the first or second aspect. In the third aspect, the girder (4) constituting one side vertical edge (104) of the corner (101) where the arch rib (5) is located is a corner girder (41) or an intermediate girder (42) whose short-side length (L21) in a plan view is equal to or less than half of its long-side length (L11).

[0092] According to the third aspect, the arch rib (5) is formed on the beam portion (4) which is formed so as to have a short length (L21) and tends to have insufficient bending rigidity, thereby improving bending rigidity.

[0093] The fourth aspect can be realized by combining with any one of the first to third aspects. In the fourth aspect, the upper deck portion (2) has a belt recess (26) in a part of the outer periphery in a plan view that is recessed inward more than other parts. The belt recess (26) is formed in a part that corresponds to the arch rib (5) in a plan view, and a spot rib (52) extending upward toward the belt recess (26) is formed on the surface of the arch rib (5) as seen from the opening direction of the fork insertion opening (10) where the arch rib (5) is located.

[0094] According to the fourth aspect, deformation of the pallet (1) when a belt is hung on the belt recess (26) is suppressed.

[0095] The fifth aspect can be realized by combining with the fourth aspect. In the fifth aspect, the spat rib (52) is located at the center of the belt recess (26) in the circumferential direction of the upper deck portion (2) in a plan view.

[0096] According to the fifth aspect, the spat ribs (52) can receive the force from the belt in a balanced manner.

[0097] The sixth aspect can be realized by combining with the fourth or fifth aspect. In the sixth aspect, at least two spot ribs (52) are formed on one arch rib (5).

[0098] According to the sixth aspect, deformation of the pallet (1) when the belt is hung on the belt recess (26) can be further suppressed. [Explanation of symbols]

[0099] 1 palette 10 Fork insertion port 101 Corner 102 Upper lateral edge 103 Lower lateral edge 104 Side vertical edge 2 Upper deck section 26 Belt recess 3 Lower deck section 4 digit part 41 Corner beam 42 Intermediate girder 43 Center beam 5 Arch rib 50 Arch 52 Spat Ribs

Claims

1. An upper deck portion formed in a rectangular shape in a plan view; A lower deck portion formed in a rectangular shape in a plan view; a girder portion; The girder portion is Corner beams connecting each corner of the upper deck portion and each corner of the lower deck portion, Intermediate girders connecting the intermediate portions of each side of the upper deck portion and the intermediate portions of each side of the lower deck portion, a central girder connecting the central portion of the upper deck portion and the central portion of the lower deck portion, A pallet formed in a rectangular shape in a plan view, in which a fork insertion port is formed between the upper deck portion and the lower deck portion, and between the corner beam and the intermediate beam, The fork insertion opening is formed in a rectangular shape in a side view, having an upper horizontal edge and a lower horizontal edge that are parallel to each other, and a pair of side vertical edges that are parallel to each other, A pallet characterized in that an arch rib that forms the corner is formed on the upper deck portion located at the corner formed by one of the pair of side vertical edges of the fork insertion opening and the upper horizontal edge, and has an arch portion that is arch-shaped in side view and protrudes so that it positions downward as it approaches the one side vertical edge that forms this corner.

2. A pallet as described in claim 1, characterized in that the girder portion that constitutes one of the vertical edges of the corner where the arch rib is located is a corner girder or an intermediate girder that is formed so that its short-side length in a planar view is shorter than its height.

3. A pallet as described in claim 1, characterized in that the girder portion that constitutes one of the vertical edges of the corner where the arch rib is located is a corner girder or an intermediate girder whose short-side length in a plan view is less than half of its long-side length.

4. the upper deck portion has a belt recess in a part of an outer peripheral edge in a plan view, the belt recess being recessed inward relative to other parts, The belt recess is formed in a portion corresponding to the arch rib in a plan view, 2. A pallet according to claim 1, characterized in that a spot rib extending upward toward the belt recess is formed on the surface of the arch rib when viewed from the opening direction of the fork insertion port where the arch rib is located.

5. 5. The pallet according to claim 4, wherein the spot rib is located at the center of the belt recess in the circumferential direction of the upper deck portion in a plan view.

6. 5. A pallet according to claim 4, wherein at least two of said spot ribs are formed on one of said arch ribs.

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