Tray and blank

Abstract

To provide a tray allowing for making the workability of assembling favorable while assuring appropriate stacking.SOLUTION: A tray 1 comprises one pair of first sidewalls 11 that are provided upright at both ends in a longitudinal direction of a bottom wall 10, one pair of second sidewalls 12 that are provided upright at both ends in a left-right direction of the bottom wall 10, two pairs of inner flaps 13 that extend from both ends in a left-right direction of the one pair of first sidewalls 11 in a manner getting close to each other and face inner surfaces of the one pair of second sidewalls 12, and one pair of crosspieces 15 that extend from upper ends of the one pair of second sidewalls 12 in a manner getting close to each other and cover the inner flaps 13. The inner flap 13 has a stack protrusion 22 protruding upward, and the crosspiece 15 has a penetration hole 30 allowing the stack protrusion 22 to pass through. The stack protrusion 22 is formed in a mountain form by bending a tip side of a projection piece 23 extending upward from an upper end of the inner flap 13 inward, so that a tip 25A of the projection piece 23 is engaged with a front edge 30A of the penetration hole 30 by a restoration force of the bent projection piece 23.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to vertically stackable trays and blanks. [Background technology]

[0002] A tray is known in which a pair of first side walls and a pair of second side walls are erected on the edge of a bottom wall (Patent Document 1). An inner wall is connected to the side end of the first side wall and is arranged to face the inner surface of the second side wall, and a batten is connected to the upper end of the second side wall and is arranged to cover the inner wall. A stacking protrusion is protruded from the upper end of the inner wall, and a through hole is formed in the batten to allow the stacking protrusion to pass through. A stacking hole is formed in the bottom wall into which the stacking protrusion of a lower tray engages when multiple trays are stacked vertically. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-85444 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above technology, the stacking protrusions are structurally weak because they are as thick as one piece of material (corrugated cardboard sheet). Therefore, when multiple trays are stacked and the upper tray moves laterally, the stacking protrusions of the lower trays may break or be crushed.

[0005] Here, in consideration of the ease of assembling the tray (workability), it is preferable that the through holes of the battens are formed larger than the stacking protrusions of the inner wall, so that the stacking protrusions can be inserted into the through holes with some play. However, if the stacking protrusions have a large play, the inner wall is not held in a position facing the inner surface of the second side wall, and may move away from the inner surface of the second side wall and tilt toward the center of the tray. This causes problems such as the inner wall (its tip) interfering with the contents contained in the tray. In response to this, if the stacking protrusions of the inner wall are tightly fitted into the through holes of the battens in order to hold the inner wall in a position in contact with the inner surface of the second side wall, it becomes difficult to insert the stacking protrusions into the through holes, which causes a problem of poor workability in assembling the tray.

[0006] In consideration of the above circumstances, the present invention provides a tray and blank that can improve the workability in assembly while ensuring proper stacking. [Means for solving the problem]

[0007] The present invention relates to a vertically stackable tray, comprising: a bottom wall on which an article to be packaged is placed; a pair of first side walls erected at both ends of the bottom wall in a first direction; a pair of second side walls erected at both ends of the bottom wall in a second direction perpendicular to the first direction; two pairs of inner flaps extending from both ends of the pair of first side walls in the second direction so as to approach each other and facing inner surfaces of the pair of second side walls; and a pair of inner flaps extending from upper ends of the pair of second side walls so as to approach each other and covering the inner flaps. and a pair of rib portions, wherein the inner flap has a stacking protrusion protruding upward, the rib portion has a through hole allowing the stacking protrusion to pass through, and the bottom wall has a stacking hole for engaging the stacking protrusion of the lower tray when a plurality of the trays are stacked, and the stacking protrusion is formed into a mountain shape by bending inward the tip side of a protrusion piece extending upward from the upper end of the inner flap, and the restoring force of the bent protrusion piece engages the tip of the protrusion piece with the leading edge of the through hole.

[0008] In this case, the protrusion piece has a base end protrusion protruding upward from the upper end of the inner flap, and a tip protrusion that includes the tip end of the protrusion piece and is connected to the upper end of the base end protrusion via a protrusion fold line, and when the first side wall and the second side wall are erected, the slat portion extends upward from the upper end of the second side wall, and the inner flap faces the inner surface of the second side wall, the protrusion piece extends beyond the leading edge of the through hole and a portion including the protrusion fold line faces the through hole, and the tip protrusion becomes one with the slat portion while engaging the tip end with the leading edge of the through hole and bends inward along the protrusion fold line, so that the bent portion of the protrusion piece at the protrusion fold line protrudes upward through the through hole.

[0009] In this case, when the first side wall and the second side wall are erected, the batten portion extends upward from the upper end of the second side wall, and the inner flap faces the inner surface of the second side wall, the protruding fold line faces the through hole at any position between an upper limit position that is 1 / 3 of the total height of the through hole lower than the leading edge of the through hole, and a lower limit position that is the center of the total height of the through hole.

[0010] The blank of the present invention forms any of the trays described above. Effect of the Invention

[0011] According to the present invention, proper stacking of trays can be ensured while improving the workability in assembly. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a perspective view showing a tray according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing a tray blank according to one embodiment of the present invention. [Diagram 3] 11A to 11C are perspective views showing a process of assembling a tray according to an embodiment of the present invention. [Figure 4]1 is a side view of a portion of a tray according to an embodiment of the present invention, showing the positional relationship between a protruding piece and a through hole. [Diagram 5] 1 is a cross-sectional view of a portion of a tray according to an embodiment of the present invention, showing a state in which the rail portions have begun to be folded in the normal direction. [Figure 6] 11 is a cross-sectional view of a portion of a tray according to an embodiment of the present invention, illustrating a process in which a bent portion of a protruding piece passes through a through hole of a rail portion. FIG. [Figure 7] 1 is a cross-sectional view showing a part of a tray according to one embodiment of the present invention in which a stacking convex portion has been formed. [Figure 8] FIG. 2 is a cross-sectional view of a portion of a tray according to one embodiment of the present invention, showing a state in which a plurality of trays are stacked. [Figure 9] FIG. 11 is a plan view showing a tray blank according to a first modified example of the embodiment of the present invention. [Figure 10] 10A to 10C are perspective views showing a process of assembling a tray according to a first modified example of the embodiment of the present invention. [Figure 11] FIG. 11 is a plan view showing a tray blank according to a second modified example of the embodiment of the present invention. [Figure 12] 10A to 10C are perspective views showing a process of assembling a tray according to a second modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. Note that Fr, Rr, L, R, U, and D shown in the drawings indicate front, rear, left, right, top, and bottom. The front-rear direction (first direction), left-right direction (second direction), and up-down direction are mutually perpendicular. Terms indicating directions and positions are used in this specification, but these terms are used for convenience of explanation and do not limit the technical scope of the present invention. In addition, the terms indicating directions and positions are based on the directions and positions in the state in which the tray is assembled and used.

[0014] A tray 1 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the tray 1. Figure 2 is a plan view showing a blank 1A of the tray 1.

[0015] 1, the tray 1 is formed in a generally rectangular parallelepiped shape with an open top, with a pair of first side walls 11 and a pair of second side walls 12 erected on the periphery of a bottom wall 10. An item to be packaged (not shown) is placed on the bottom wall 10, and the trays 1 are formed so that they can be stacked vertically while containing the item to be packaged.

[0016] The tray 1 is formed from a blank 1A shown in FIG. 2. The blank 1A is formed by punching out a single piece of cardboard sheet made of paper using a die or the like. The cardboard sheet is, for example, a double-sided cardboard sheet in which a wavy core 9A is laminated with liners on both the front and back sides. Note that FIG. 2 shows the front (outer) side. In this specification, the direction parallel to the core 9A of the cardboard sheet is referred to as the "corrugation direction", and the direction perpendicular to the corrugation direction is referred to as the "flow direction". In the drawings, "X" indicates the "corrugation direction", and "Y" indicates the "flow direction".

[0017] [blank] As shown in Fig. 2, the blank 1A includes a bottom wall 10, a pair of first side walls 11, a pair of second side walls 12, two pairs (four) of inner flaps 13, two pairs (four) of upper end flaps 14, and a pair of rib portions 15. Note that in Fig. 2, the pair of first side walls 11 are formed symmetrically in the left-right direction, the pair of second side walls 12 and the pair of rib portions 15 are formed symmetrically in the top-bottom direction, and the four inner flaps 13 and the four upper end flaps 14 are formed symmetrically in the top-bottom direction and the left-right direction with respect to the bottom wall 10, so that in this specification, mainly one of each portion will be described.

[0018] <Bottom wall, first side wall, second side wall> The bottom wall 10 is formed in a generally rectangular shape that is long in the flow direction. The pair of first side walls 11 are connected to both ends of the bottom wall 10 in the step direction (first direction) via a first folding line L1. The pair of second side walls 12 are connected to both ends of the bottom wall 10 in the flow direction (second direction) via a second folding line L2. The first side wall 11 and the second side wall 12 are each formed in a generally rectangular shape. The dimension (height) of the second side wall 12 in the flow direction is set to be slightly longer (higher) than the dimension (height) of the first side wall 11 in the step direction.

[0019] (1st folding line) The first fold line L1 is curved so as to bulge toward the first side wall 11 (outside in the step direction). Specifically, the middle part of the first fold line L1 in the flow direction is a straight line part that is approximately parallel to the flow direction, and both sides of the first fold line L1 in the flow direction that sandwich the straight line part are curved parts that bulge outward in the step direction as they move away from the straight line part. Therefore, the bottom wall 10 is formed in a quadrangular shape (drum shape) in which the middle part bulges (becomes wider) than both sides in the flow direction. In addition, the upper end edge of the first side wall 11 (excluding the upper end flap 14 described later) is curved so as to bulge outward in the step direction like the first fold line L1. Note that the first fold line L1 and the upper end edge of the first side wall 11 are not limited to being curved, and may be formed, for example, in a broken line shape bent into an approximately trapezoidal shape (not shown).

[0020] (Layered holes) Two pairs (four) of stacking holes 20 are opened in the bottom wall 10 along the boundary line (second fold line L2) between the bottom wall 10 and the pair of second side walls 12. The second fold line L2 is formed approximately parallel to the row direction, and a pair of stacking holes 20 adjacent to one second fold line L2 are drilled at a distance from each other in the row direction. The stacking holes 20 are formed in a roughly rectangular shape and divide the second fold line L2. Although details will be described later, the stacking protrusions 22 of the lower tray 1 engage (are inserted) into the stacking holes 20 when multiple trays 1 are stacked.

[0021] (handle hole) A handle hole 16 having a substantially pentagonal shape is drilled in the approximate center of the second side wall 12. A pair of cushioning pieces 17 are connected to the outside of the handle hole 16 in the flow direction via a gripping fold line L7. When a user carrying the tray 1 places his / her hand on the upper edge of the handle hole 16, the cushioning pieces 17 are bent inward along the gripping fold line L7, increasing the area that touches the hand. This prevents the upper edge of the handle hole 16 from digging into the user's hand, reducing the strain on the user's hand. The handle hole 16 (the cushioning pieces 17, the gripping fold line L7) may be omitted (not shown).

[0022] <Inner flap> The two pairs of inner flaps 13 are connected to both ends of the pair of first side walls 11 in the flow direction via the third fold line L3. The inner flaps 13 are formed in a roughly rectangular shape. The (upper end edge (outer end edge in the step direction) of the inner flaps 13 inclines so as to move away from the second side wall 12 as it moves away from the first side wall 11 in the flow direction. In other words, the four inner flaps 13 extend so as to spread radially from both ends of the pair of first side walls 11 in the flow direction. The dimension (extension dimension) of the inner flaps 13 in the flow direction is set to be slightly shorter than half the dimension of the second side wall 12 in the step direction.

[0023] A substantially rectangular stack evacuation recess 21 is recessed in the lower part of the inner flap 13 (part facing the second side wall 12). The stack evacuation recess 21 is formed so as to avoid the stack hole 20 in the bottom wall 10 when the tray 1 is assembled (see FIG. 1). Among the lower end sides (sides facing the second side wall 12) of the inner flap 13, the lower end side on the base end side (first side wall 11 side) of the stack evacuation recess 21 in the flow direction is substantially parallel to the side of the second side wall 12, and the lower end side on the tip side of the stack evacuation recess 21 in the flow direction is inclined so as to move away from the side of the second side wall 12 toward the tip in the flow direction. In other words, the groove formed between the second side wall 12 and the inner flap 13 is formed so as to gradually become wider toward the outside in the step direction. The side of the second side wall 12 is formed in a straight line parallel to the flow direction.

[0024] Furthermore, a generally trapezoidal handle retraction recess 18 is recessed at the leading end side in the flow direction of the inner flap 13. The handle retraction recess 18 is formed so as to avoid the handle hole 16 (the buffer piece 17) when the tray 1 is assembled (see FIG. 1). If the handle hole 16 is omitted, the handle retraction recess 18 may be omitted (not shown).

[0025] (projection piece) A protruding piece 23 is connected to the upper end edge of the inner flap 13. The protruding piece 23 extends upward (outside in the step direction) from the upper end of the inner flap 13. The protruding piece 23 has a base end protrusion 24 protruding upward from the upper end of the inner flap 13, and a tip protrusion 25 connected to the upper end (outer end in the step direction) of the base end protrusion 24 via a protrusion fold line L8. The base end protrusion 24 is formed seamlessly and integrally with the inner flap 13. The base end protrusion 24 and the tip protrusion 25 are each formed in a substantially trapezoidal shape, and are connected so that the upper bases of the trapezoids butt against each other. In other words, the protruding piece 23 is formed in a polygonal shape having a constriction near the center in the step direction. The dimension (height) in the step direction of the tip protrusion 25 is set to be longer (higher) than the dimension (height) in the step direction of the base end protrusion 24. Although details will be described later, by bending the tip side (tip protrusion 25) of the protrusion piece 23 inward, a mountain-shaped (inverted V-shape) laminated convex portion 22 is formed so as to protrude upward from the inner flap 13.

[0026] <Top flap> The two pairs of upper end flaps 14 are connected to the tips (upper end edges) of the pair of first side walls 11 in the step direction via the fourth fold line L4. The pair of upper end flaps 14 connected to one first side wall 11 are arranged at both ends in the flow direction with a gap between them in the flow direction. The upper end flaps 14 are formed in a substantially rectangular shape. A locking hole 26 is formed in the boundary between the upper end flaps 14 and the first side wall 11 so as to divide the fourth fold line L4. The locking hole 26 is formed in a substantially triangular shape with oblique sides approaching each other from the upper end flaps 14 toward the first side wall 11.

[0027] <Beam> The pair of ribs 15 are connected to the leading ends (upper ends) of the pair of first side walls 11 in the flow direction via the fifth fold line L5. The ribs 15 are formed in a generally rectangular shape, with both sides in the step direction protruding toward the leading end in the flow direction. The pair of ribs 15 have two pairs (four) of through holes 30 open along the boundary line (fifth fold line L5) with the pair of second side walls 12. The pair of through holes 30 adjacent to one fifth fold line L5 are drilled at an interval from each other in the step direction, and the interval is approximately the same as the interval between the pair of stacking holes 20. The through holes 30 are formed in a generally rectangular shape and divide the fifth fold line L5. The dimension (total height H1) of the through holes 30 in the flow direction is set slightly shorter than the dimension (groove width H2) of the stacking holes 20 in the flow direction. In other words, the stacking holes 20 are formed narrower than the through holes 30. Further, the overall height H1 of the through hole 30 is set shorter than the dimension in the step direction (total length FL) of the above-mentioned protruding piece 23. Although details will be described later, the through hole 30 is a hole through which the laminated protruding portion 22 protruding upward from the inner flap 13 passes.

[0028] Locking pieces 27 are connected to both ends in the step direction of the crosspiece 15 and to the leading end in the flow direction via sixth fold lines L6. Locking pieces 27 gradually become thinner toward the outside in the step direction and are slightly curved toward the first side wall 11. A base portion of the locking piece 27 is narrowed, and a return portion is formed on the outside of the base side of the locking piece 27 in the flow direction.

[0029] The first to sixth fold lines L1 to L6, the gripping fold line L7 and the protruding fold line L8 are general-purpose creases formed by indenting the cardboard sheet from the back side, but are not limited thereto. Any structure that allows the cardboard sheet to be folded in the desired direction may be used, such as a lead crease formed by perforating a general-purpose crease.

[0030] [Assembling the tray] Next, an example of an assembly operation of the tray 1 will be described with reference to Fig. 1 and Fig. 3 to Fig. 6. Fig. 3 is a perspective view showing the process of assembling the tray 1. Fig. 4 is a side view showing the positional relationship between the protrusion 23 and the through hole 30. Fig. 5 is a cross-sectional view showing the state where the crosspiece 15 has started to be folded forward. Fig. 6 is a cross-sectional view showing the process where the bent portion of the protrusion 23 passes through the through hole 30 of the crosspiece 15. Fig. 7 is a cross-sectional view showing the state where the stacking protrusion 22 has been formed.

[0031] The tray 1 is assembled by appropriately folding the blank 1A with the back surface (inner surface) facing upward. Here, the process in which a box-making machine (not shown) automatically assembles the tray 1 from the blank 1A is described, but the tray 1 may also be assembled manually by an operator. In this specification, folding the cardboard sheet so that the back surface faces inward is referred to as a "normal fold."

[0032] A plurality of blanks 1A are set in a box-making machine, which assembles (manufactures) trays 1 as follows. As shown in FIG. 3, a pair of first side walls 11 are folded forward along a first folding line L1 and erected on both ends of the bottom wall 10 in the front-rear direction (first direction). Then, two pairs of inner flaps 13 are folded forward along a third folding line L3 and extended from both ends of the pair of first side walls 11 in the left-right direction (second direction) so as to approach each other. The inner flaps 13 stand up along both ends of the bottom wall 10 in the left-right direction, and the stacking evacuation recesses 21 of the inner flaps 13 face the stacking holes 20 of the bottom wall 10. The front and rear pair of inner flaps 13 have their tips close to each other (or lightly touching each other).

[0033] Since the first fold line L1, which is the boundary line between the bottom wall 10 and the first side wall 11, is formed to bulge outward, when the pair of first side walls 11 are erected, the bottom wall 10 has an arch shape that is warped upwardly convex when viewed from the side (see FIG. 5, etc.). Although it is not clear from the drawing, the lower part of the pair of first side walls 11 has a shape in which the middle part in the left-right direction when viewed from a plane bulges outward, so the pair of first side walls 11 are inclined outward from the lower part to the upper part. In addition, since the two pairs (four) of inner flaps 13 are extended radially, the inner flaps 13 are inclined slightly upward from the base end (third fold line L3) to the tip. Of the lower end sides of the inner flaps 13, the base end side from the stacking evacuation recess 21 contacts the upper surface of the bottom wall 10, and the tip side from the stacking evacuation recess 21 is slightly floating from the upper surface of the bottom wall 10 (or is in weaker contact than the base end side).

[0034] Next, the pair of second side walls 12 are folded forward along the second folding line L2 and erected at both ends of the bottom wall 10 in the left-right direction (second direction) (in FIG. 3, only the right second side wall 12 is erected). The pair of second side walls 12 are in an erect position and cover the outer surfaces of the two pairs of inner flaps 13, and the pair of crosspieces 15 extend upward from the upper ends of the pair of second side walls 12. The inner flaps 13 face the inner surfaces of the second side walls 12, and the protruding pieces 23 face the inner surfaces of the crosspieces 15 (through holes 30).

[0035] 4, the positional relationship between the protruding piece 23 of the inner flap 13 and the through hole 30 of the crosspiece 15 will be described in detail. When the first side wall 11 and the second side wall 12 are erected, the crosspiece 15 extends upward from the upper end of the second side wall 12, and the inner flap 13 faces the inner surface of the second side wall 12, the (tip side of) the protruding piece 23 extends (upward) beyond the tip edge 30A (upper edge) of the through hole 30, and a part of it including the protruding fold line L8 faces the through hole 30.

[0036] Specifically, the tip 25A of the protruding piece 23 (tip protruding portion 25) engages with the tip edge portion 30A of the through hole 30. That is, the tip 25A of the tip protruding portion 25 overlaps the inner surface of the crosspiece 15 at a position higher than the tip edge portion 30A of the through hole 30. Next, most of the protruding piece 23 (middle portion) including the protruding fold line L8 is disposed within the range of the through hole 30 and is in a state where it can be seen from the outside through the through hole 30. In detail, the protruding piece 23 has the protruding fold line L8 facing upward from the center of the total height H1 of the through hole 30. More specifically, the protruding fold line L8 faces the through hole 30 at any position (within a range) between an upper limit position UL that is 1 / 3 of the total height H1 of the through hole 30 lower than the tip edge portion 30A of the through hole 30, and a lower limit position LL that is the center of the total height H1. Next, the base end 24A (upper end side of the inner flap 13) of the protruding piece 23 (base end protrusion 24) overlaps with the base edge 30B (lower edge (inner surface of the crosspiece 15)) of the through hole 30. In other words, the base end 24A of the base end protrusion 24 is located lower than the base edge 30B (fifth fold line L5) of the through hole 30.

[0037] Returning to the explanation of the assembly of tray 1, the box-making machine folds the top flap 14 along the fourth fold line L4 (see Figure 3), folds the locking piece 27 along the sixth fold line L6, and folds the rail portion 15 along the fifth fold line L5 while inserting the locking piece 27 into the locking hole 26 of the top flap 14 (see Figures 1, 5 to 7).

[0038] As described above, since the tip 25A of the tip projection 25 is engaged with the leading edge 30A of the through hole 30 (see Figs. 3 and 4), the crosspiece 15 is folded while pushing the tip projection 25 down inward (see Fig. 5). As shown in Figs. 5 and 6, in the process of tilting the erected crosspiece 15 inward, the tip projection 25 becomes one with the crosspiece 15 (together with the crosspiece 15) while engaging the tip 25A with the leading edge 30A of the through hole 30, and is bent (tilted) inward along the protruding fold line L8. As shown in Fig. 7, the tip projection 25 is folded back so that the inner surface faces the base projection 24, forming a mountain-shaped laminated convex portion 22. Since the protruding fold line L8 faces slightly above the through hole 30 (see FIG. 4), the apex of the laminated protruding portion 22 (the bent portion of the protruding piece 23 at the protruding fold line L8) protrudes upward through the through hole 30 from the inside to the outside (see FIGS. 5 to 7). A restoring force (repulsive force) acts on the protruding piece 23 bent at the protruding fold line L8 to straighten the bend around the protruding fold line L8 (see the thick arrow (broken line) shown in FIG. 7). Therefore, the tip portion 25A of the protruding piece 23 is held in a state of being engaged with the leading edge portion 30A of the through hole 30 by the restoring force of the bent protruding piece 23. The "mountain shape" formed by the laminated protruding portion 22 refers to a shape that gradually tapers from the bottom to the top and is an inverted V-shape with the protruding fold line L8 as the apex, and refers to a shape in which the angle between the base end protruding portion 24 and the tip end protruding portion 25 is an acute angle (excluding 0 degrees).

[0039] 1 and 7, the crosspiece 15 is bent until it assumes a substantially horizontal position (contacting the upper end of the inner flap 13) while inserting the locking piece 27 into the locking hole 26 of the upper end flap 14. By inserting the locking piece 27 into the locking hole 26, the crosspiece 15 is fixed to the upper end flap 14 (first side wall 11). The pair of crosspieces 15 extend from the upper ends of the pair of second side walls 12 so as to approach each other and cover the two pairs of inner flaps 13 (the upper ends of the inner flaps 13).

[0040] As shown in Fig. 1 and Fig. 7, when the crosspiece 15 covers the upper end of the inner flap 13, the lamination protrusion 22 protrudes upward from the through hole 30. As shown in Fig. 7, the base end protrusion 24 stands upright substantially vertically from the upper end of the inner flap 13, and its base end 24A (lower part) is disposed below the through hole 30 (not exposed). The tip protrusion 25 is inclined downward from the upper end of the base end protrusion 24 toward the inside (center in the left-right direction), and its tip 25A is disposed below the through hole 30 (not exposed). In addition, the tip 25A of the tip protrusion 25 engages with the leading edge 30A of the through hole 30, and a restoring force (see the thick arrow (broken line) shown in Fig. 7) acts on the bent part of the protruding piece 23, so that the lamination protrusion 22 expands in the left-right direction to fill the through hole 30 when viewed from above. Furthermore, since the laminated convex portion 22 is inserted into the through hole 30 while maintaining the restoring force at the bent portion, the inner flap 13 is subjected to the restoring force and is urged (pressed) toward the inner surface of the second side wall 12 (see the thick arrow (solid line) shown in Figure 7)).

[0041] This completes the assembly of the tray 1 (see FIG. 1). The worker places the packaged item on the bottom wall 10 of the assembled tray 1. The arch-shaped bottom wall 10 keeps the packaged item above the ground surface GL, such as the floor (see FIG. 7, etc.), preventing impacts from being directly transmitted from the ground surface GL to the packaged item, thereby protecting the packaged item.

[0042] In the tray 1 according to this embodiment, the inner flap 13 overlaps the inner surface of the second side wall 12 without being bonded, and is held down from above by the rib portion 15. Although not clear in the drawings, the inner flap 13 is supported immovably with the tip side pressed down toward the bottom wall 10. The lower end edge of the base end side of the inner flap 13 is pressed against the bottom wall 10 with a greater pressing force than the lower end edge of the tip side, and the lower end edge of the tip side is slightly separated from (or lightly in contact with) the bottom wall 10. By pressing down the tip side of the inner flap 13, both ends in the left-right direction of the first side wall 11 are drawn inward (toward the center in the front-rear direction) (inclined inward). The first side wall 11 is folded at the curved first folding line L1 and tries to be inclined outward in the front-rear direction, but by inclining both ends in the left-right direction inward, it is held in an upright position except for both sides in the left-right direction. The first side wall 11 is not entirely inclined inward in the front-rear direction, but both ends in the left-right direction are slightly inclined inward, and gradually opens outward toward the center in the left-right direction. The angle between both ends in the left-right direction of the first side wall 11 and the bottom wall 10 is less than 90 degrees (acute angle), but the angle between the center of the first side wall 11 in the left-right direction and the bottom wall 10 is about 90 degrees (or slightly obtuse angle). According to this configuration, since both the left and right sides of the first side wall 11 are inclined inward, it is easy to stack multiple trays 1, and since the middle part in the left-right direction of the first side wall 11 is in an upright position, sufficient pressure resistance can be ensured. In addition, the base end side of the inner flap 13 can be pressed against the bottom wall 10 to improve the pressure resistance of the tray 1. In addition, since the stacking protrusion 22 penetrates the through hole 30, the pair of first side walls 11 are restricted from tilting outward.

[0043] [Stacking effect of trays] Next, the stacking action of the trays 1 will be described with reference to FIG. 8. FIG. 8 is a perspective view showing a state in which the trays 1 are stacked. Here, for ease of explanation, a case in which two trays 1 are stacked will be described. In this specification, for convenience of explanation, the tray 1 located at the bottom will also be called the "lower tray 1 (D)" and each component of the lower tray 1 (D) will be given the reference symbol "(D)", and the tray 1 located at the top will also be called the "upper tray 1 (U)" and each component of the upper tray 1 (U) will be given the reference symbol "(U)". In the explanation common to the lower tray 1 (D) and the upper tray 1 (U), the reference symbols "(D)" and "(U)" will be omitted.

[0044] The worker places the upper tray 1(U) on the lower tray 1(D) placed on the ground surface GL in the same orientation as the lower tray 1(D). The four stacking protrusions 22(D) of the lower tray 1(D) fit into the four stacking holes 20(U) of the upper tray 1(U). Since the stacking protrusions 22 are formed in a mountain shape (approximately a right-angled triangle shape) tapering upward when viewed from the front, the stacking protrusions 22(D) can be smoothly inserted into the stacking holes 20(U) even if the stacking holes 20 are formed narrower in the left-right direction than the through holes 30. The groove width H2 (see FIG. 2) of the stacking holes 20 may be equal to or greater than the thickness of the base end protrusions 24 and the tip end protrusions 25 stacked in close contact with each other and equal to or less than the total height H1 of the through holes 30. Therefore, the lamination protrusion 22(D) that has expanded to fill the through hole 30 may be inserted into the lamination hole 20(U) while narrowing the angle between the tip protrusion 25 and the base end protrusion 24 (not shown). In this case, in the process of inserting the lamination protrusion 22(D) into the lamination hole 20(U), the tip protrusion 25 may rotate about the projection fold line L8 so as to approach the base end protrusion 24, and the tip portion 25A may be separated from the leading edge portion 30A of the through hole 30 (not shown). In this way, by forming the lamination protrusion 22 into a mountain shape, the trays 1 can be stacked properly even if the lamination hole 20 in the bottom wall 10 is a small opening.

[0045] In addition, since the bottom wall 10 is arch-shaped, both left and right ends of the bottom wall 10(U) of the upper tray 1(U) abut against a pair of rails 15(D) of the lower tray 1(D), but the left-right middle part of the bottom wall 10(U) (the lower end of the first side wall 11(U)) faces the upper end of the first side wall 11(D) of the lower tray 1(D) with a small gap between them. When a compressive load is applied to the bottom wall 10(U), the lower end of the first side wall 11(U) abuts against the upper end of the first side wall 11(D) of the lower tray 1(D) (not shown).

[0046] As a result of the above, the upper tray 1(U) is stacked on the lower tray 1(D). Because the stacking protrusions 22(D) fit into the stacking holes 20(U), the upper tray 1(U) is restricted from moving in the horizontal direction relative to the lower tray 1(D).

[0047] In the tray 1 according to the present embodiment described above, the first side wall 11 and the second side wall 12 are erected, the inner flap 13 faces the inner surface of the second side wall 12, the crosspiece 15 covers the inner flap 13, the protruding piece 23 extending upward from the upper end of the inner flap 13 is folded in half to form the stacking protrusion 22, and the stacking protrusion 22 penetrates the through hole 30 opened in the crosspiece 15 (see FIG. 7). According to this configuration, the stacking protrusion 22 is formed into a mountain shape by bending the tip side (tip protrusion 25) of the protruding piece 23 inward, so that the structural strength (rigidity) of the stacking protrusion 22 can be improved compared to the case where the stacking protrusion 22 is a single plate-like shape. As a result, even if the upper tray 1 (U) moves laterally in a state where multiple trays 1 are stacked, the stacking protrusion 22 (D) of the lower tray 1 (D) is prevented from being broken or crushed.

[0048] In addition, when the stacking protrusion 22 is formed, the tip 25A of the protrusion 23 engages with the leading edge 30A of the through hole 30 due to the restoring force of the bent protrusion 23 (see the thick arrow (broken line) in FIG. 7). With this configuration, the stacking protrusion 22 functions as a leaf spring inserted into the through hole 30 in a compressed state, and can urge the inner flap 13 in the opposite direction to the leading edge 30A of the through hole 30 and press it against the inner surface of the second side wall 12 (see the thick arrow (solid line) in FIG. 7). This prevents the inner flap 13 from tilting toward the center of the tray 1 when viewed from above, and can maintain the inner flap 13 in a position overlapping the inner surface of the second side wall 12. As a result, the inner flap 13 does not narrow the storage space of the tray 1, and can be prevented from interfering with the packaged item placed on the bottom wall 10.

[0049] Moreover, the through hole 30 may be formed to a size that allows the bent portion of the lamination protrusion 22 to pass through, and that allows the lamination protrusion 22 to maintain its mountain shape even if it is expanded by the restoring force of the bent portion. According to this configuration, since it is not necessary to tightly fit the lamination protrusion 22 into the through hole 30, the through hole 30 can be formed relatively large. This makes it easier to insert the lamination protrusion 22 into the through hole 30, and improves the workability of assembling the tray 1. Furthermore, when viewed from above, the lamination protrusion 22 expands due to the restoring force of the folded portion of the protrusion piece 23, and substantially blocks the through hole 30. This prevents the through hole 30 from being exposed on the assembled tray 1, and improves the aesthetic appeal of the tray 1.

[0050] In addition, in the tray 1 according to the present embodiment, when the second side wall 12 is erected, the crosspiece 15 extends upward from the upper end of the second side wall 12, and the inner flap 13 faces the inner surface of the second side wall 12, the protruding piece 23 extends beyond the leading edge 30A of the through hole 30, and a part of the protruding piece 23 including the protruding fold line L8 faces the through hole 30 (see FIG. 4). According to this configuration, the leading end 25A of the leading end protrusion 25 engages with the leading edge 30A of the through hole 30, so that the leading end protrusion 25 can be bent along the protruding fold line L8 simply by tilting the crosspiece 15 inward. In addition, since the protruding fold line L8 faces the through hole 30, the bent portion (protruding fold line L8) protruding upward can be smoothly passed through the through hole 30 as the leading end protrusion 25 is bent. This allows the automatically formed bent portion of stacking protrusion 22 to protrude upward from through hole 30 in conjunction with the tilting of crosspiece 15. As a result, compared to a case in which crosspiece 15 and protruding piece 23 are bent separately, the assembly work of tray 1 can be made easier and the time and effort required for the assembly work can be reduced.

[0051] In addition, in the tray 1 (blank 1A) according to this embodiment, the through hole 30 has an upper limit UL set at a position 1 / 3 of the total height H1 below the leading edge 30A (upper end), a lower limit LL set at the center of the total height H1, and the protruding fold line L8 faces the through hole 30 at any position between the upper limit UL and the lower limit LL (see FIG. 4). With this configuration, the stacking protrusion 22 can be automatically formed in conjunction with the inclination of the crosspiece 15, and the bent portion of the stacking protrusion 22 can be protruded upward from the through hole 30 with almost certainty. The applicant has experimentally confirmed that by setting the positional relationship between the protruding fold line L8 and the through hole 30 within the above range, the operation of protruding the bent portion of the stacking protrusion 22 from the through hole 30 occurs with an extremely high probability. This makes it possible to assemble the tray 1 using a box-making machine, and to mass-produce the tray 1 in a short time. As a result, it is possible to reduce the manufacturing cost of the tray 1.

[0052] In the tray 1 (blank 1A) according to the present embodiment, the first fold line L1 is curved so as to bulge outward in the front-rear direction, but the present invention is not limited thereto. For example, the first fold line L1 may be formed as a straight line parallel to the flow direction, and the entire first side wall 11 may be configured to be substantially upright with respect to the bottom wall 10 (not shown). In this case, the upper end edge of the first side wall 11 may also be a straight line parallel to the first fold line L1 (not shown). In addition, the two pairs of inner flaps 13 extend radially, but the present invention is not limited thereto. For example, each inner flap 13 may extend parallel to the first side wall 11 so as not to draw the first side wall 11 inward (not shown).

[0053] [First Modification] Next, a tray 2 (blank 2A) according to a first modified example of this embodiment will be described with reference to Figures 9 and 10. Figure 9 is a plan view showing the blank 2A ​​of the tray 2 according to the first modified example. Figure 10 is a perspective view showing the process of assembling the tray 2 according to the first modified example. In the following description, the same components as those of the above-mentioned tray 1 (blank 1A) are given the same reference numerals, and the same description will be omitted.

[0054] In the previously described tray 1 (blank 1A), the first side wall 11 and the inner flap 13 each have a single wall structure, and the upper end flap 14 is connected to the upper end of the first side wall 11. In contrast, in the tray 2 (blank 2A) according to the first modified example, the upper end flap 14 is omitted, and the first side wall 31 and the inner flap 33 each have a double wall structure. Note that in the tray 2 according to the first modified example, the handle hole 16, the hand retraction recess 18, and the like are also omitted.

[0055] Each of the pair of first side walls 31 has a first outer wall 41 and a first inner wall 42, and each of the two pairs of inner flaps 33 has an outer piece 44 and an inner piece 45. In Fig. 9, the pair of first side walls 31 are formed symmetrically, and each of the four inner flaps 33 is formed symmetrically in the up-down and left-right directions with the bottom wall 10 as the center, so this specification will mainly describe one portion of each.

[0056] The first outer wall 41 is connected to the end of the bottom wall 10 in the step direction via the first fold line L1, and the first inner wall 42 is connected to the tip of the first outer wall 41 in the step direction via a pair of eleventh fold lines L11. A first frame portion 43 is formed between the pair of eleventh fold lines L11, connecting the first outer wall 41 and the first inner wall 42. The width (dimension in the step direction) of the first frame portion 43 is approximately twice the thickness of the corrugated cardboard sheet. The locking hole 26 is drilled from the first frame portion 43 to the upper part of the first outer wall 41. The first fold line L1 and the pair of eleventh fold lines L11 are formed linearly along the flow direction and approximately parallel to each other.

[0057] The outer piece 44 is connected to the end of the first outer wall 41 in the flow direction via the third fold line L3, and the inner piece 45 is connected to the end of the first inner wall 42 in the flow direction via the twelfth fold line L12. The outer piece 44 and the inner piece 45 extend substantially parallel to the first outer wall 41 and the first inner wall 42. The end of the inner piece 45 in the flow direction is shifted toward the center in the flow direction from the end of the outer piece 44 in the flow direction. In addition, the twelfth fold line L12 is slightly shifted toward the center in the flow direction from the third fold line L3. A gap is formed between the outer piece 44 and the inner piece 45, and a stacking evacuation recess 21 is recessed in the lower part of the outer piece 44 and the inner piece 45 on the opposite side of the gap. A protruding piece 23 is connected to the upper end edge of the outer piece 44 (the edge facing the inner piece 45 across the gap). The protruding piece 23 extends from the upper end of the outer piece 44 so as to bite into the inner piece 45. The tip projection 25 of the protruding piece 23 (including the tip side of the base end projection 24) is partitioned into the inner piece 45 by a cutting line.

[0058] The eleventh fold line L11 is a general-purpose crease, and the twelfth fold line L12 is a reverse crease that dents the cardboard sheet from the front side, but the crease is not limited to these and may be any structure that folds the cardboard sheet in a desired direction. In this specification, folding the cardboard sheet so that the front side faces inward is called a "reverse fold."

[0059] When assembling the tray 2 according to the first modification, as shown in FIG. 10, the first outer wall 41 is folded forward along the first folding line L1, and the first frame portion 43 and the first inner wall 42 are folded forward along a pair of eleventh folding lines L11. The first inner wall 42 faces the inner surface (rear surface) of the first outer wall 41, and the first frame portion 43 is provided between the first outer wall 41 and the first inner wall 42. The first outer wall 41 and the first inner wall 42 form the first side wall 31 having a double-wall structure, and the first side wall 31 is erected at the end of the bottom wall 10 in the front-rear direction. The inner piece 45 is folded inward together with the first inner wall 42, and faces the inner surface of the outer piece 44. The outer piece 44 and the inner piece 45 form the inner flap 33 having a double-wall structure. As the inner piece 45 is folded back, the protruding piece 23 is hollowed out from the inner piece 45 and protrudes relatively upward.

[0060] Next, the two pairs of inner flaps 33 are folded from both ends of the pair of first side walls 31 in the left-right direction so as to approach each other. In detail, the outer piece 44 is folded forward along the third folding line L3, and the inner piece 45 is folded backward along the twelfth folding line L12. Next, the second side wall 12 is folded forward along the second folding line L2, the crosspiece 15 is folded forward along the fifth folding line L5, and the locking piece 27 folded forward along the sixth folding line L6 is inserted into the locking hole 26 of the first frame portion 43. In addition, in the process of folding the crosspiece 15, the protruding piece 23 is folded in half to form the stacking protrusion 22, and the stacking protrusion 22 penetrates the through hole 30 opened in the crosspiece 15 (see also FIG. 6). The tip portion 25A of the protruding piece 23 forming the stacking protrusion 22 engages with the leading edge portion 30A of the through hole 30 (see also FIG. 7).

[0061] This completes the assembly of the tray 2. Note that the assembled tray 2 will have a shape roughly similar to that of the tray 1 (see FIG. 1) described above, and therefore the assembled tray 2 will not be shown in the drawings.

[0062] The tray 2 (blank 2A) of the first modified example described above can improve the structural strength of the stacking convex portion 22 and can maintain the inner flap 33 in a position overlapping the inner surface of the second side wall 12, thereby achieving effects similar to those of the tray 1 (blank 1A) described previously.

[0063] In the tray 2 (blank 2A) according to the first modified example of this embodiment, the outer piece 44 and the inner piece 45 are separated by a gap, but this is not limited thereto, and the outer piece 44 and the inner piece 45 may be connected by a frame portion (not shown) as in the first side wall 31. In addition, the protruding piece 23 is connected to the upper end edge of the outer piece 44, but this is not limited thereto, and the protruding piece 23 may be connected to the upper end edge of the inner piece 45 (not shown). In this case, it is preferable that the protruding fold line L8 of the protruding piece 23 is a reverse crease line.

[0064] [Second modified example] Next, a tray 3 (blank 3A) according to a second modified example of this embodiment will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is a plan view showing a blank 3A of a tray 3 according to the second modified example. Fig. 12 is a perspective view showing a process of assembling a tray 3 according to the second modified example. In the following description, the same components as those of the above-mentioned trays 1 and 2 (blanks 1A and 2A) are given the same reference numerals, and the same description will be omitted.

[0065] In the tray 2 (blank 2A) according to the first modification, the first side wall 31 and the inner flap 33 each have a double-wall structure, but in the tray 3 (blank 3A) according to the second modification, the first side wall 31 has a double-wall structure, but the inner flap 13 has a single-wall structure, which is different. In addition, two pairs of second inner pieces 46 are connected to both ends of the pair of second side walls 12 in the step direction. Note that the handle hole 16, the hand retraction recess 18, etc. are also omitted in the tray 3 according to the second modification. In addition, in FIG. 11, the four inner flaps 13 and the four second inner pieces 46 are each formed symmetrically in the up-down and left-right directions with the bottom wall 10 as the center, so this specification will mainly describe one part of each.

[0066] The inner flap 13 is connected to the end of the first inner wall 42 in the flow direction via a twelfth fold line L12. A stacking evacuation recess 21 is recessed into the tip (lower part) of the inner flap 13 in the step direction, and a protrusion 23 is connected to the center (upper part) of the inner flap 13 in the step direction. The second inner flap 46 is connected to the end of the second side wall 12 in the step direction via a thirteenth fold line L13. An outer corner of the second inner flap 46 is cut out to avoid interference with the protrusion 23.

[0067] In addition, the thirteenth fold line L13 is a general-purpose crease, but is not limited thereto and may be any structure that folds the cardboard sheet in a desired direction. In addition, in the tray 3 according to the second modification, the protruding fold line L8 of the protruding piece 23 is a reverse crease.

[0068] When assembling the tray 3 according to the second modification, the second side wall 12 is folded forward along the second fold line L2, and the second inner piece 46 is folded forward along the thirteenth fold line L13, as shown in Fig. 12. The pair of second side walls 12 are erected at both ends of the bottom wall 10 in the left-right direction, and the four inner flaps 13 are erected along both ends of the bottom wall 10 in the front-rear direction. The crosspiece 15 extends upward from the upper end of the second side wall 12 and is flush with the second side wall 12.

[0069] Next, the first outer wall 41 is folded forward along the first fold line L1, the inner flap 13 is folded backward along the twelfth fold line L12, and the first frame portion 43 and the first inner wall 42 are folded forward along a pair of eleventh fold lines L11. The first inner wall 42 faces the inner surface (back surface) of the first outer wall 41 across the pair of left and right second inner pieces 46, and the first frame portion 43 is installed between the first outer wall 41 and the first inner wall 42. As a result, the first side wall 31, which is a double wall, is erected at the end of the bottom wall 10 in the front-rear direction. The inner flap 13 faces the inner surface of the second side wall 12, and the protruding piece 23 faces the through hole 30 of the crosspiece 15 from the inside.

[0070] Next, the crosspiece 15 is folded forward along the fifth fold line L5, and the locking piece 27 folded forward along the sixth fold line L6 is inserted into the locking hole 26 of the first frame portion 43. During the process of folding the crosspiece 15, the protruding piece 23 is folded in half to form the lamination protrusion 22, which penetrates the through hole 30 opened in the crosspiece 15 (see also FIG. 6). The tip 25A of the protruding piece 23 that formed the lamination protrusion 22 engages with the leading edge 30A of the through hole 30 (see also FIG. 7).

[0071] This completes the assembly of the tray 3. Note that the assembled tray 3 will have a shape roughly similar to that of the tray 1 (see FIG. 1) described above, and therefore the assembled tray 3 will not be shown in the drawings.

[0072] The tray 3 (blank 3A) of the second modified example described above can improve the structural strength of the stacking convex portion 22 and can maintain the inner flap 13 in a position overlapping the inner surface of the second side wall 12, thereby achieving effects similar to those of the tray 1 (blank 1A) described previously.

[0073] In the trays 1 to 3 (blanks 1A to 3A) according to the present embodiment (including the first and second modified examples, the same applies below), one stacking protrusion 22 (projection piece 23) is provided to protrude from each of the inner flaps 13, 33, but the present invention is not limited to this. For example, the stacking protrusion 22 (projection piece 23) may be provided to protrude from only one of the pair of front and rear inner flaps 13, 33, or two or more stacking protrusions 22 (projection pieces 23) may be provided to protrude from each of the inner flaps 13, 33 (not shown). In these cases, a through hole 30 may be drilled in the crosspiece 15 according to the number and arrangement of the stacking protrusions 22 (projection pieces 23) (not shown). In addition, the tips of the pair of front and rear inner flaps 13, 33 are slightly spaced from each other, but the present invention is not limited to this, and the tips of the pair of front and rear inner flaps 13, 33 may be butted against each other or overlap each other (not shown).

[0074] In addition, in the trays 1 to 3 according to the present embodiment, the stacking protrusion 22 is formed in a substantially right-angled triangle shape when viewed from the front (see FIG. 7), but the present invention is not limited to this. For example, the base end protrusion 24 may be connected to the inner flaps 13, 33 via a fold and slightly inwardly inclined along the fold (not shown). In other words, the base end protrusion 24 and the tip protrusion 25 may be formed in a substantially triangular shape inclined with respect to a vertical straight line (not shown).

[0075] In addition, in the trays 1 to 3 (blanks 1A to 3A) according to the present embodiment, the crosspiece 15 is formed to be bridged between a pair of first side walls 11, but the present invention is not limited thereto. For example, two independent second crosspieces may be provided on both the front and rear sides of the upper end of the second side wall 12, and a through hole 30 may be provided in each of the second crosspieces (not shown). In addition, the crosspiece 15 is fixed by inserting the locking piece 27 of the crosspiece 15 into the locking hole 26 formed in the upper end flap 14 or the first frame portion 43, but the present invention is not limited thereto. For example, the upper end flap 14 having the locking hole 26 may be provided on the end of the crosspiece 15 in the front-rear direction (step direction), and the locking piece 27 may be provided on the upper end of the first side wall 11 (not shown). Also, for example, the locking pieces 27 and locking holes 26 may be omitted, and the crosspieces 15 may be fixed to the upper end flap 14 or the first side walls 11, 31 using adhesive tape, glue, or the like (not shown).

[0076] In addition, in the trays 1 to 3 (blanks 1A to 3A) according to the present embodiment, the protruding fold line L8 faces the through hole 30 at a position between the upper limit position UL and the lower limit position LL, but the present invention is not limited to this. For example, when assembling the trays 1 to 3 without using a box-making machine and an operator manually assembles the trays 1 to 3, the protruding fold line L8 may face the through hole 30 in a range other than the upper limit position UL to the lower limit position LL (not shown). However, in consideration of the ease of assembling the trays 1 to 3, the applicant has confirmed through experiments that it is preferable for the protruding fold line L8 to face the through hole 30 in the range from the upper limit position UL to the lower limit position LL even when assembling the trays manually.

[0077] Moreover, the trays 1-3 (blanks 1A-3A) according to this embodiment are formed from double-sided cardboard sheets made of paper, but are not limited thereto, and may be formed from single-sided or double-sided cardboard sheets, thick paper, or resin boards (sheets), etc. Furthermore, the dimensions (width, depth, height) and shapes of each part of the tray 1, the thickness of the cardboard sheets, the direction in which the core 9A extends, etc. may be freely changed.

[0078] The above embodiment shows one aspect of the tray and blank according to the present invention, and the technical scope of the present invention is not limited to the above embodiment. The present invention may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea, and the claims include all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0079] 1,2,3 Tray 1A, 2A, 3A Blank 10 Bottom wall 11,31 First side wall 12 Second side wall 13,33 Inner flap 15 Cross section 20 Stacking holes 22 Laminated protrusion 23 Projection piece 24 Proximal protrusion 25 Tip protrusion 25A tip 30 through holes 30A leading edge H1 Height L8 protruding fold line LL lower limit position UL upper limit position

Claims

1. A vertically stackable tray (1, 2, 3), A bottom wall (10) on which the packaged item is placed; A pair of first side walls (11, 31) erected on both ends of the bottom wall in a first direction; A pair of second side walls (12) erected on both ends of the bottom wall in a second direction perpendicular to the first direction; two pairs of inner flaps (13, 33) extending from both ends of the pair of first side walls in the second direction so as to approach each other and facing inner surfaces of the pair of second side walls; a pair of rails (15) extending from upper ends of the pair of second side walls so as to approach each other and cover the inner flaps; The inner flap has a lamination protrusion (22) protruding upward, The crosspiece has a through hole (30) through which the lamination protrusion passes, The bottom wall has a stacking hole (20) for engaging the stacking protrusion of the lower tray when a plurality of the trays are stacked, The stacking convex portion is formed into a mountain shape by bending inward the tip side of a protrusion (23) extending upward from the upper end of the inner flap, and the restoring force of the bent protrusion causes the tip portion (25A) of the protrusion to engage with the leading edge portion (30A) of the through hole.

2. The protruding piece is A base end protrusion (24) protruding upward from the upper end of the inner flap; a tip protrusion (25) including the tip portion of the protrusion piece and connected to an upper end of the base end protrusion via a protrusion fold line (L8); When the first side wall and the second side wall are erected, the rib portion extends upward from an upper end of the second side wall, and the inner flap faces an inner surface of the second side wall, the protruding piece extends beyond the leading edge of the through hole and a part including the protruding fold line faces the through hole, The tray of claim 1, characterized in that the tip protrusion engages with the leading edge of the through hole and bends inwardly along the protrusion fold line to become one with the crosspiece, so that the bent portion of the protrusion piece at the protrusion fold line passes through the through hole and protrudes upward.

3. The tray of claim 2, characterized in that when the first side wall and the second side wall are erected, the rib portion extends upward from the upper end of the second side wall, and the inner flap faces the inner surface of the second side wall, the protruding fold line faces the through hole at any position between an upper limit position (UL) that is 1 / 3 of the total height (H1) of the through hole from the leading edge of the through hole, and a lower limit position (LL) that is the center of the total height of the through hole.

4. A blank for forming a tray according to any one of claims 1 to 3.

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