Pallet

Abstract

To provide a pallet which has stable shape quality.SOLUTION: A pallet 10 has such a cylindrical structure that a plurality of side girder parts 20 positioned on both sides of a pair of fork insertion paths 90 penetrate in a vertical direction and have widths of 50 [mm] or less, wherein a middle position in a vertical direction of inward side walls 21 of the respective side girder parts 20 approaches a position closer to the outward side wall 22 than the end so that intervals between the inward side walls 21 and outward side walls 22 become narrower at a position closer to the middle position than the end in the vertical direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a resin pallet and a method for manufacturing the same. [Background technology]

[0002] A known example of this type of pallet is one in which multiple reinforcing walls are arranged in parallel to bridge the upper and lower openings of the cylindrical wall that forms the outer shell of the girder, and the upper and lower reinforcing walls are arranged in a staggered pattern (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 10-35669 A (Figs. 1 and 2, paragraph

[0013] ) Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for smaller pallets so that multiple pallets can be laid out efficiently. To meet this demand, it is necessary to reduce the width of the side girders by moving the outer surfaces of the multiple side girders on both sides of a pair of fork insertion paths inward. However, if the width of the side girders is reduced while maintaining the structure of the conventional pallet described above, the protrusions of the mold used to mold the interior of the side girders will become elongated and thin, which can cause deformation due to resin pressure during molding, resulting in variations in the shape of the pallet. Therefore, this disclosure provides a technology for stabilizing the shape quality of pallets. [Means for solving the problem]

[0005] The invention of claim 1, made to solve the above problem, is a resin pallet in which a plurality of side girders located on both sides of a pair of fork insertion paths when a pair of forks of a hand lifter or forklift is inserted between a plurality of girders from a first horizontal direction form a cylindrical structure that penetrates in the vertical direction and has a width of 50 mm or less in a second horizontal direction perpendicular to the first horizontal direction, and in which the intermediate positions of the inward side walls in the vertical direction are closer to the outward side walls than the ends so that the distance between the inward side walls and outward side walls facing each other in the second horizontal direction of each of the side girders is narrower at the intermediate positions than at the ends in the vertical direction.

[0006] The invention of claim 2 is a pallet as described in claim 1, in which the middle region of the inward side wall located on the side of the fork insertion path is offset toward the outward side wall more than the upper region located above.

[0007] The invention of claim 3 is a pallet as described in claim 2, which has a curved portion between the upper region and the middle region of the inward side wall so that the upper corner of the fork insertion path on the side girder portion side when viewed from the first horizontal direction has an R-chamfered shape.

[0008] The invention of claim 4 is a pallet as described in claim 2 or 3, wherein the multiple girders are arranged in three rows and three columns, and the lower ends of adjacent girders in the second horizontal direction are connected by a lower end connecting wall, and the upper corners of the pair of fork insertion paths viewed from the first horizontal direction have an R-chamfered shape in the middle part in the first horizontal direction and have a pin-angled shape at both ends in the first horizontal direction, and the lower corners of the pair of fork insertion paths viewed from the first horizontal direction have an R-chamfered shape in the middle part and both ends in the first horizontal direction.

[0009] The invention of claim 5 is a pallet described in any one of claims 1 to 4, in which only one of the inward side walls, above or below the intermediate region located to the side of the fork insertion path, is offset away from the outward side wall, and the mold parting line is located inside the side girder portion, closer to the other side above or below the intermediate region.

[0010] The invention of claim 6 is a resin pallet in which a plurality of side girders located on both sides of a pair of fork insertion paths when a pair of forks of a hand lifter or forklift is inserted between a plurality of girders from a first horizontal direction form a cylindrical structure that penetrates in the vertical direction and has a width of 50 mm or less in a second horizontal direction perpendicular to the first horizontal direction, and the middle part in the vertical direction is carved out by the fork insertion path.

[0011] The invention of claim 7 is a method for manufacturing a pallet using a resin injection molding mold to manufacture a pallet having a cylindrical structure in which a plurality of side girders located on both sides of a pair of fork insertion paths when a pair of forks of a hand lifter or forklift is inserted from a first horizontal direction between a plurality of girders penetrate in the vertical direction and have a width of 50 mm or less in a second horizontal direction perpendicular to the first horizontal direction, wherein a first molding protrusion protruding from a first mold and a second molding protrusion protruding from the second mold are made thicker at their base ends than at their tips to form the inner surfaces of the side girders of a first and second mold that face each other in the mold opening direction of the injection molding mold, and the tip surfaces of the first molding protrusion and the second molding protrusion are abutted against each other at a vertical midpoint within the side girders. [Effects of the Invention]

[0012] In the pallets of claims 1 and 6, the multiple side girders on both sides of a pair of fork insertion paths extending in the first horizontal direction have a width in the second horizontal direction of 50 mm or less, which allows the overall width of the pallet (width in the second horizontal direction) to be reduced by 100 mm or more compared to general conventional pallets whose width is 100 mm or more, thereby enabling the pallet to be laid out efficiently. Furthermore, in order to mold the inner surfaces of the side girders, it was previously necessary to provide elongated molding protrusions in the injection molding mold that were approximately the same height as the overall height of the side girders. However, in the pallets of claims 1 and 6 of the present disclosure, the side girders have a cylindrical structure that penetrates in the vertical direction, so the molding protrusions for molding the inner surfaces of the side girders can be divided into first and second molding protrusions that face each other in the mold opening direction of the injection molding mold, making them shorter than conventional molding protrusions.

[0013] This suppresses deformation of the first and second molding protrusions due to resin pressure, stabilizing the shape quality of the pallet. Furthermore, in claim 1, the vertical midpoint of the inward side wall is closer to the outward side wall than the end so that the distance between the inward side wall and the outward side wall of each side girder that face each other in the second horizontal direction is narrower at a midpoint than at the vertical end of the side girder. This allows the first molding protrusion or the second molding protrusion to be shaped so that its base end is thicker than its tip end. Also, in claim 6, the vertical midpoint is hollowed out by the fork insertion passage, allowing the first molding protrusion and the second molding protrusion to be shaped so that its base end is thicker than its tip end. These factors also increase the bending strength of the first molding protrusion and the second molding protrusion, suppressing deformation of the molding protrusions due to resin pressure and stabilizing the shape quality of the pallet.

[0014] The width of the pallet can be reduced by having the fork insertion passage bite into the side girder to the point where the middle region of the inward side wall located to the side of the fork insertion passage is offset toward the outward side wall from the upper region located above, as in the pallet of claim 2. In this case, if a curved portion is provided between the upper region and middle region of the inward side wall so that the upper corner on the side girder side has an R-chamfered shape, as in the pallet of claim 3, stress concentration is prevented, strength is increased, and water is less likely to accumulate between the middle region and upper region of the inward side wall.

[0015] In the configuration of claim 4, the same effects as those of claim 3 are achieved in the girder portion at the middle part in the first horizontal direction.

[0016] In the pallet of claim 5, only one of the inward side walls of the side girder, either above or below the intermediate region located to the side of the fork insertion path, is offset away from the outward side wall, so that of the first and second molded protrusions that mold the inside of the side girder, only one of the base ends above or below the intermediate region has a thick shape. However, the mold parting line is located inside the side girder, closer to the other side above or below the intermediate region. In other words, molded protrusions with thinner base ends are shorter than molded protrusions with thicker base ends, making it easier to ensure strength.

[0017] In the pallet manufacturing method of claim 7, the molding protrusions for molding the inner surfaces of the side girders can be divided into first and second molding protrusions that face each other in the mold opening direction of the injection molding mold, making them shorter than conventional molding protrusions. This reduces deformation of the first and second molding protrusions due to resin pressure, stabilizing the shape quality of the pallet. Moreover, because both the first and second molding protrusions are thicker at their base ends than at their tips, the bending strength of the first and second molding protrusions is also increased, reducing deformation of the molding protrusions due to resin pressure and stabilizing the shape quality of the pallet.

[0018] The contacting tip surfaces of the first and second forming protrusions may be perpendicular to the contact direction or may be inclined. Furthermore, the tip surfaces are not limited to flat surfaces, but may be correspondingly uneven or curved surfaces. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of the top side of a pallet according to an embodiment of the present disclosure. [Figure 2] Perspective view of the underside of the pallet [Figure 3] Cross-sectional view of the girder [Figure 4] A perspective view of a part of the side girder at the end in the vertical direction. [Figure 5] Front cross section of the side girder at the longitudinal end DETAILED DESCRIPTION OF THE INVENTION

[0020] A pallet 10 according to one embodiment of the present disclosure will now be described with reference to Figures 1 to 5. Pallet 10 according to this embodiment is an injection-molded resin product, and as shown in Figure 1, has a rectangular planar shape, with the vertical direction H1 being larger than the horizontal direction H2 of the rectangle.

[0021] Deck board 11 of pallet 10 has a crosspiece structure and includes a plurality of vertical ribs 11A extending in the vertical direction H1 and a plurality of horizontal ribs 11B extending in the horizontal direction H2. Furthermore, both end portions and the center portion of deck board 11 in the vertical direction H1 are provided with horizontal reinforcing portions 12 that make the spacing between horizontal ribs 11B closer than throughout deck board 11. Furthermore, horizontal outer edge reinforcing portions 13 are provided on the edges of both portions in the vertical direction H1 that further close the spacing between any two horizontal ribs 11B included in horizontal reinforcing portions 12 and that close the vertical ribs 11A only between those two horizontal ribs 11B.

[0022] Deck board 11 is provided at both edge portions in the horizontal direction H2 with vertically elongated outer edge reinforcement portions 14, which are configured by extending horizontally elongated outer edge reinforcement portions 13 vertically. Furthermore, deck board 11 is provided at the center in the horizontal direction H2 with vertically elongated central reinforcement portion 15, in which vertical ribs 11A are closely spaced and the upper surface is covered with top plate 15T. Top plate 15T is also provided with a rectangular hole that is slightly smaller than the square surrounded by vertical ribs 11A and horizontal ribs 11B of vertically elongated central reinforcement portion 15.

[0023] As shown in Fig. 1, cylindrical grip receiving tubes 16 are formed integrally with horizontally elongated outer edge reinforcement sections 13 near the four corners of deck board 11, and anti-slip members 16G are housed inside these grip receiving tubes 16, which protrude slightly from the upper surface of deck board 11. Also, as shown in Fig. 2, a sloped surface 11G is formed on the outer edge of the underside of deck board 11, and a vertical display surface 11N is formed without sloped surface 11G in part of the area that serves as the entrance to fork insertion path 90. A sticker that identifies the user or owner of pallet 10 can be affixed to display surface 11N.

[0024] The four areas of deck board 11 surrounded by the reinforcing portions (reference numerals 12, 13, 14, and 15) described above form inner lattice portions 19, which have larger square grid structures than the reinforcing portions. Each inner lattice portion 19 is integrally formed with a square cylindrical grip receiving tube 17 at a lower position, and anti-slip members 17G are housed inside these tubes, which protrude slightly from the underside of deck board 11.

[0025] The girder sections 20, 30 of the pallet 10 are arranged in three rows and three columns, positioned at the four corners of the deck board 11, the centers of the outer edges of each of the four sides, and the center of the entire deck board 11, and protrude downward from the deck board 11. Furthermore, the lower ends of the girder sections 20, 30 adjacent to each other in the horizontal direction H2 are connected by a lower end connecting wall 40. The lower end connecting wall 40 has a structure in which the entire upper surface of a group of ribs 40L (see FIG. 2) that intersect in a cross-piece structure is covered by a top wall 40T (see FIG. 1). Furthermore, as shown in FIG. 1, the center of the top wall 40T in the width direction (longitudinal direction H1) forms a horizontal section 40S, and on both sides in the width direction, there are inclined oblique sections 40U that bend downward from the horizontal section 40S. Furthermore, as shown in Figure 2, cylindrical grip receiving tubes 46 are integrally formed in the ribs 40L of the four lower end connecting walls 40 located at both ends of the vertical direction H1, and are capable of accommodating anti-slip members (not shown) inside them.

[0026] In the pallet 10 of this embodiment, a pair of forks of a hand lifter or forklift can be inserted below the deck board 11 from any of the vertical direction H1 and horizontal direction H2. When arranging a plurality of pallets 10 in a densely packed state, arranging the pallets 10 side by side in the direction of their short sides makes it easier to transport each pallet 10, so a pair of forks are inserted below the deck board 11 from the vertical direction H1. Therefore, in the pallet 10 of this embodiment, the girders 20 on both sides of the pair of fork insertion paths 90 when inserting a pair of forks from the vertical direction H1 have a different structure from conventional ones in order to make the width of the pallet 10 compact.

[0027] That is, in this embodiment, the vertical direction H1 corresponds to the "first horizontal direction" in the claims, and the horizontal direction H2 corresponds to the "second horizontal direction" in the claims. In addition, when distinguishing between the girders 20, 30, the girders 20 on both sides of the pair of fork insertion paths 90 when inserting a pair of forks from the vertical direction H1 will be referred to as the "side girders 20," and the girder 30 between the pair of fork insertion paths 90 will be referred to as the "center girder 30."

[0028] The planar shape of the aforementioned anti-slip members 17G is an elongated rectangle, and the four anti-slip members 17G are arranged so as to be rotationally symmetrical. Whether the forks are inserted into the deck board 11 from the vertical direction H1 or the horizontal direction H2, the anti-slip member 17G extending in the longitudinal direction of one fork and the anti-slip member 17G extending in the width direction of the other fork abut against each fork. The pallet 10 has a bilaterally symmetrical structure in both the vertical direction H1 and the horizontal direction H2, except for the anti-slip members 17G and the grip receiving tubes 17.

[0029] The following mainly describes in detail the structure of the girder sections 20, 30. Figure 3(A) shows the planar cross-sectional shapes of the girder sections 20, 30 at the ends in the vertical direction H1, and Figure 3(B) shows the planar cross-sectional shapes of the girder sections 20, 30 at the center in the vertical direction H1. As shown in these figures, the girder sections 20, 30 are both structured with reinforcing ribs 24, 34 within the cylindrical walls 25, 35. Furthermore, while the planar cross-sectional shape of the cylindrical wall 35 of the center girder section 30 is approximately square, the planar cross-sectional shape of the cylindrical walls 25 of the side girder sections 20 is a rectangle that is longer in the vertical direction H1.

[0030] In order to guide the forks into a pair of fork insertion passages 90, the cylindrical walls 25, 35 of the girder sections 20, 30 arranged at the ends of the vertical direction H1 have side walls (symbols 21, 31) of the cylindrical walls 25, 35 of the girder sections 20, 30 facing each other across the fork insertion passage 90 that are curved apart at the ends on the outer surface side of the pallet 10.

[0031] The length and width L2, L3 of the square cross-sectional shape of the cylindrical wall 35 of the central girder 30 and the length L2 in the vertical direction H1 of the rectangular cross-sectional shape of the cylindrical wall 25 of the side girder 20 are the same, both being, for example, 80 to 150 mm. Furthermore, the length L1 in the horizontal direction H2 of the side girder 20 is 1 / 5 to 1 / 3 of the length L2 in the vertical direction H1, for example, 50 mm or less (preferably 40 mm or less, and even more preferably 30 mm or less).

[0032] The reinforcing rib 34 of the central girder 30 has a cross-shaped planar cross section, dividing the interior of the cylindrical wall 35 into two equal parts in both the vertical direction H1 and the horizontal direction H2, whereas the reinforcing rib 24 of the side girder 20 divides the interior of the cylindrical wall 25 into two equal parts only in the vertical direction H1. The cylindrical wall 35 of the central girder 30 is provided with a reinforcing rib 35L protruding from the inner surface of the cylindrical wall 35.

[0033] As shown in Figure 1, the cylindrical wall 35 of the central girder 30 has a structure in which the upper surface is closed by the top plate 15T and the entire lower surface is open. In contrast, as shown in Figures 4 and 5, the cylindrical wall 25 of the side girder 20 has an open upper surface and an open lower surface, penetrating vertically.

[0034] Furthermore, as shown in Figures 4 and 5, of the inward side wall 21 and outward side wall 22 that face each other in the horizontal direction H2 of the tubular wall 25 of the side girder 20, the outward side wall 22 has a flat plate shape, while the inward side wall 21 has a shape in which the middle part in the vertical direction is hollowed out by the fork insertion passage 90, and the detailed shape differs between the side girder 20 located at the end in the vertical direction H1 and the side girder 20 located in the center.

[0035] 4, at the side girder portion 20 at the end in the vertical direction H1, the vertical middle portion of the inward side wall 21 is bent in a crank shape to correspond to the fork insertion passage 90. The inward side wall 21 has a first vertical portion 21A that is parallel to the outward side wall 22 above the fork insertion passage 90, a horizontal portion 21B that is bent at a right angle from the lower end of the first vertical portion 21A toward the outward side wall 22, a second vertical portion 21C that is bent at a right angle substantially vertically downward from the end of the horizontal portion 21B facing the outward side wall 22, an arc portion 21D that is bent from the lower end of the second vertical portion 21C toward the side away from the outward side wall 22, and a third vertical portion 21E that is bent vertically downward from the end of the arc portion 21D that is away from the outward side wall 22 and is located directly below the first vertical portion 21A. The arc portion 21D gives the lower corner of the fork insertion path 90 on the side girder portion 20 side a rounded chamfered shape, and the horizontal portion 21B and the second vertical portion 21C give the upper corner of the fork insertion path 90 on the side girder portion 20 side a pin-angle shape.

[0036] 5, the side girder 20 at the center in the vertical direction H1 has a first vertical portion 21A similar to the side girder 20 at the end, a curved portion 21F that curves downward from the lower end of the first vertical portion 21A toward the outward side wall 22, and a second vertical portion 21G that extends from the lower end of the curved portion 21F to the lower end of the side girder 20. The curved portion 21F gives the fork insertion passage 90 an R-chamfered shape at the upper corner on the side girder 20 side.

[0037] In addition, the end of the upper surface wall 40T of the lower end connecting wall 40 in the horizontal direction H2 is provided with an arc-shaped curved, rising arc portion 42 that is connected to the second vertical portion 21G so that the lower corners of the fork insertion path 90 on the side girder 20 side also have an R-chamfered shape. Similarly, with respect to the central girder 30 at the center and end in the vertical direction H1, an arc portion 41 that rises from the upper surface wall 40T is provided and connected to the side wall 31 of the central girder 30 so that the lower corners of the fork insertion path 90 on the side girder 30 side have an R-chamfered shape.

[0038] Furthermore, with regard to the central girder 30 in the center of the vertical direction H1, as shown in Figure 5, a corner protrusion 43 protrudes from the side wall 31 of the central girder 30 so that the upper corner of the fork insertion passage 90 on the central girder 30 side also has an R-chamfered shape, and corner extensions 11C extend from multiple horizontal ribs 11B included in the horizontal reinforcement portion 12, forming a continuous R-chamfered surface 11D between the corner protrusion 43 and the corner extensions 11C.

[0039] On the other hand, as for the central girder 30 at the end of the vertical direction H1, as shown in Figure 4, the upper corner of the fork insertion passage 90 on the central girder 30 side is pin-angle shaped, and the lower surfaces of the multiple horizontal ribs 11B included in the horizontal reinforcement portion 12 are perpendicular to the side wall 31 of the central girder 30, without having the above-mentioned corner protrusion 43 and corner extension portion 11C.

[0040] As shown in FIG. 4, an inner surface ridge 29 is formed on the inner surface of the side girder 20 at the end in the vertical direction H1, approximately in the vertical center, protruding slightly from the inner surface of the side girder 20. Also, as shown in FIG. 5, an inner surface ridge 29 is formed on the inner surface of the side girder 20 at the center in the vertical direction H1, approximately below the vertical center, protruding slightly from the inner surface of the side girder 20. These inner surface ridges 29 are formed by the gap between the joint surfaces of the first molding ridges and the second molding ridges described below. In other words, the inner surface ridges 29 serve as parting lines between the molds within each side girder 20. Furthermore, in FIGS. 4 and 5, the portion of the inner surface of the inward sidewall 21 that appears parallel to the vertical direction at first glance is gradually inclined away from the inner surface of the outward sidewall 22 as it moves upward and downward away from the inner surface ridge 29.

[0041] This completes the description of the structure of the pallet 10 of this embodiment. The pallet 10 of this embodiment is manufactured using a resin injection mold. Although not shown, the injection mold includes first and second molds that open and close in the vertical direction of the pallet 10, a pair of first slide molds that move toward and away from each other in the vertical direction H1 to mold the outer surface of the pallet 10 facing the vertical direction H1 and have a pair of rectangular pillars that form the inner surfaces of the pair of fork insertion passages 90, and a pair of second slide molds that move toward and away from each other in the horizontal direction H2 to mold the opposing surfaces of the side beams 20 adjacent in the vertical direction H1. The inner surfaces of the beams 20, 30 are molded by molding protrusions that protrude from the first and second molds in the vertical direction of the pallet 10.

[0042] Specifically, the molding protrusion (not shown) that molds the inner surface of the central beam 30 (hereinafter referred to as the "molding protrusion for the central beam 30") has a structure in which square pillars are arranged in two rows and two columns, similar to the shape of the part of the central beam 30 that does not have a resin wall shown in Figure 3. Furthermore, since the upper surface of the cylindrical wall 35 of the central beam 30 is closed by the top plate 15T, the molding protrusion for the central beam 30 protrudes from one of the first or second molds and has a length that extends from the lower end of the central beam 30 to the underside of the top plate 15T.

[0043] In contrast, the molding protrusions (not shown) that form the inner surfaces of the side girders 20 (hereinafter referred to as "molding protrusions for side girders 20") have a structure consisting of two rectangular pillars arranged side by side, in accordance with the shape of the portion of the side girders 20 without a resin wall shown in Figure 3, and the rectangular pillars of the molding protrusions for side girders 20 are thinner than the rectangular pillars of the molding protrusions for central girders 30. Taking advantage of the fact that the tubular walls 25 of the side girders 20 are perforated vertically, the molding protrusions for side girders 20 consist of a first molding protrusion protruding from a first mold and a second molding protrusion protruding from a second mold. The tip surfaces of these first and second molding protrusions are joined at a vertical midpoint of the side girders 20, and the aforementioned inner surface protrusion 29 is formed as a result of this joining. In this way, the molded protrusions for the side girders 20 are divided into a first molded protrusion and a second molded protrusion in the opening and closing direction of the first and second molds, and are therefore shorter than the molded protrusions for the central girders 30. As a result, although the molded protrusions for the side girders 20 are thinner than the molded protrusions for the central girders 30, deformation due to resin pressure is suppressed. Moreover, because the side girders 20 have a structure in which the middle part in the vertical direction is hollowed out by the fork insertion passage 90, both the first molded protrusion and the second molded protrusion at the side girders 20 at the center in the vertical direction H1 have a structure in which the base end is thicker than the tip, which also suppresses deformation of the first molded protrusion and the second molded protrusion due to resin pressure. Furthermore, in the side beam 20 at the end in the vertical direction H1, one of the first and second molded protrusions has a structure in which the base end is thicker than the tip, but their joining surfaces are arranged so that one is shorter than the other. This also balances the strength of the first and second molded protrusions, and suppresses deformation due to resin pressure.

[0044] As described above, the pallet 10 of this embodiment has a cylindrical structure in which the side girders 20 penetrate vertically. Therefore, the molding protrusions for molding the inner surfaces of the side girders 20 can be divided into first and second molding protrusions that face each other in the mold opening direction of the injection molding die, making them shorter than conventional molding protrusions. This reduces deformation of the first and second molding protrusions that mold the interior of the side girders 20 due to resin pressure, even for pallet 10 with thinner-than-normal side girders 20. Furthermore, the spacing between the inward side wall 21 and the outward side wall 22 that face each other in the lateral direction H2 of each side girder 20 is narrower at the midpoint than at both ends of the side girder 20. Therefore, the inward side wall 21 is closer to the outward side wall 22 at its midpoint than at both ends in the vertical direction. This allows the first and second molding protrusions to be thicker at their base ends than at their tip ends. These factors also increase the bending strength of the first and second molding protrusions, reducing deformation of the molding protrusions due to resin pressure. Furthermore, by suppressing deformation of the molded protrusions due to resin pressure, shape quality is stable even for pallets with side girders 20 having a width of 50 mm or less, as in the pallet 10 of this embodiment. Furthermore, because the width of the side girders 20 of the pallet 10 is 50 mm or less, the overall width of the pallet 10 (width in the horizontal direction H2) can be reduced by 100 mm or more compared to general conventional pallets 10 with a width of 100 mm or more, making it possible to efficiently lay out the pallets 10.

[0045] Furthermore, in the pallet 10 of this embodiment, the fork insertion passage 90 is recessed into the side girder 20 to a position where the middle region of the inward side wall 21 located to the side of the fork insertion passage 90 is offset toward the outward side wall 22 from the upper region located above, thereby reducing the width of the pallet 10. Also, a curved portion 21F is provided between the upper region and middle region of the inward side wall 21 so that the upper corner on the side girder 20 side has an R-chamfered shape, making it difficult for water to accumulate between the middle region and upper region of the inward side wall 21 and preventing stress concentration.

[0046] In the pallet 10 of this embodiment, the upper corners of a pair of fork insertion passages 90 when viewed from the vertical direction H1 have an R-chamfered shape in the middle part in the vertical direction H1, while they have a pin-angled shape at both ends in the vertical direction H1. Therefore, compared to when the upper corners of the fork insertion passages 90 are R-chamfered in all locations, there are fewer undercuts and the mold structure is simpler.

[0047] [Other embodiments] (1) In the above embodiment, the vertical middle portion of the side girder 20 having a width of 50 mm or less was hollowed out by the fork insertion passage 90. However, the vertical middle portion of the side girder having a width of 50 mm or more (for example, 100 mm) may be hollowed out by the fork insertion passage to reduce the overall width of the pallet.

[0048] (2) In the above embodiment, the pallet 10 is connected only between the lower ends of adjacent girder sections 20, 30 in the horizontal direction H2 by the lower end connecting wall 40, but the lower ends of adjacent girder sections in the vertical direction H1 may also be connected by a lower end connecting wall, or the entire lower surface of the pallet may be covered by a single plate.

[0049] (3) In the above embodiment, the pallet 10 has a rectangular planar shape, but it may have a square planar shape.

[0050] (4) In the pallet 10 of the above embodiment, the side girder portion 20 has a shape that is carved out by the fork insertion passage 90, but in the pallet 10 of the above embodiment, the side girder portion 20 does not have to have a shape that is carved out by the fork insertion passage 90.

[0051] (5) In the pallet 10 of the above embodiment, a pair of fork insertion passages 90 were defined by a plurality of central beams 30 in the center of the horizontal direction H2 of the pallet 10, but the central beams 30 may be removed from the center of the horizontal direction H2, and a pair of fork insertion passages 90 may not be defined.

[0052] (6) In the pallet 10 of the above embodiment, a pair of forks can be inserted not only from the vertical direction H1 but also from the horizontal direction H2. However, the pair of forks may be inserted only from the vertical direction H1. Specifically, a pair of side girders 20 may extend across the entire vertical direction H1 at both ends of the pallet 10 in the horizontal direction H2, so that the pair of forks can be inserted only from the vertical direction H1. Even in this case, the central girders 30 may be removed from the center portion in the horizontal direction H2, so that the pair of fork insertion paths 90 are not defined.

[0053] Although the present specification and drawings disclose specific examples of the technology included in the scope of the claims, the technology described in the claims is not limited to these specific examples, but also includes various modifications and variations of the specific examples, and also includes parts of the specific examples taken out alone. [Explanation of symbols]

[0054] 10 palettes 11 Deck Board 20 Side girder 21 Inward facing side wall 21F curved section 22 Outward facing sidewall 30 Central girder 30,40 digit part 31 Side wall 40 Lower connecting wall 90 Fork insertion path H1 Vertical (first horizontal) H2 Horizontal (second horizontal)

Claims

1. A resin pallet in which a plurality of side girders located on both sides of a pair of fork insertion paths when a pair of forks of a hand lifter or forklift are inserted between a plurality of girders from a first horizontal direction form a cylindrical structure that penetrates in the vertical direction and has a width of 50 mm or less in a second horizontal direction perpendicular to the first horizontal direction, and in which the intermediate positions of the inward side walls in the vertical direction are closer to the outward side walls than the ends so that the distance between the inward side walls and outward side walls facing each other in the second horizontal direction of each of the side girders is narrower at the intermediate positions than at the ends in the vertical direction.

2. 2. A pallet according to claim 1, wherein an intermediate region of said inward side wall, which is located on a side of said fork insertion passage, is offset toward said outward side wall from an upper region located above said inward side wall.

3. A pallet as described in claim 2, wherein the inward side wall has a curved portion between the upper region and the middle region so that the upper corner of the fork insertion path on the side girder side when viewed from the first horizontal direction has an R-chamfered shape.

4. The plurality of beams are arranged in three rows and three columns, and lower ends of adjacent beams in the second horizontal direction are connected by a lower end connecting wall, The upper corners of the pair of fork insertion paths as viewed from the first horizontal direction have an R-chamfered shape at a middle portion in the first horizontal direction, and have a pin-angle shape at both ends in the first horizontal direction; A pallet as described in claim 2 or 3, wherein the lower corners of the pair of fork insertion paths when viewed from the first horizontal direction have an R-chamfered shape at the middle and both end portions in the first horizontal direction.

5. Only one of the upper and lower portions of the inward side wall above and below an intermediate region located on the side of the fork insertion passage is offset away from the outward side wall. A pallet according to any one of claims 1 to 4, wherein a mold parting line is located inside the side girder portion, either above or below the intermediate region.

6. A resin pallet in which a plurality of side girders located on both sides of a pair of fork insertion paths when a pair of forks of a hand lifter or forklift are inserted between a plurality of girders from a first horizontal direction form a cylindrical structure that penetrates in the vertical direction and has a width of 50 mm or less in a second horizontal direction perpendicular to the first horizontal direction, and the middle part in the vertical direction is carved out by the fork insertion path.

7. A method for manufacturing a pallet using a resin injection mold, the method comprising the steps of: manufacturing a pallet having a cylindrical structure in which a plurality of side girders, positioned on both sides of a pair of fork insertion paths when a pair of forks of a hand lifter or a forklift are inserted from a first horizontal direction between a plurality of girders, penetrate the pallet in the vertical direction; and having a width of 50 mm or less in a second horizontal direction perpendicular to the first horizontal direction; A method for manufacturing a pallet in which a first molding protrusion protruding from a first mold and a second molding protrusion protruding from a second mold, which are opposed to each other in the mold opening direction among the injection molding molds, to form the inner surface of the side girder are made thicker at their base ends than at their tips, and the tip surfaces of the first molding protrusion and the second molding protrusion are abutted against each other at a vertical midpoint within the side girder.

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