container

Abstract

To provide a container in which an available range as an information display surface in the outer face of a side wall can be extended than ever.SOLUTION: In a container 10A of the present disclosure, an inside part from an outer edge out of inner faces of an upper side first side wall 21 and a lower side first side wall 22 is thickened to be a first thick wall part 31, and a first step part 31S following therewith is formed on an inner face, therefore, while having a thick wall part (first thick wall part 31) for a warp countermeasure, the step part (the first step part 31S) following therewith can be deleted from an outer surface. Thus, an available range as information display faces in the outer faces of the upper first side wall 21 and a lower first side wall 22 can be extended.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a resin container. [Background technology]

[0002] As this type of container, there is also known a container in which the central region of the flat portion of the side wall is made thicker than the outer edge region in order to suppress warping of the flat portion (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-69791 A (Figs. 1, 7, 9) Summary of the Invention [Problem to be solved by the invention]

[0004] The outer surface of the side wall of a container is sometimes used as an information display surface on which labels are attached or printed, but conventional containers have a problem in that a step is formed on the outer surface of the side wall due to the thick-walled portion provided to prevent warping as described above, and the information display surface is restricted by the inside of the step, making it narrow. [Means for solving the problem]

[0005] The invention of claim 1, made to solve the above problem, is a resin container having a plurality of side walls including flat side walls in which the area inside the outer edge of the outer surface is a flat area without reinforcing ribs, in which a first step portion is formed in the back area of ​​the flat area near a pair of opposing outer edges, and a first thick portion inside the first step portion is thicker than a second thick portion outside the first step portion.

[0006] The invention of claim 2 is a container described in claim 1, in which a second step portion is formed in the rear area at a position closer to the outside than the first step portion, and a third thick portion having the same thickness as the first thick portion or thicker than the first thick portion is provided outside the second step portion within the rear area.

[0007] The invention of claim 3 is a container described in claim 2, in which the first step portion and the second step portion are formed near the outer edges in the vertical and horizontal directions, and the first thick portion is surrounded on all four sides by the second thick portion, and the second thick portion is surrounded on all four sides by the third thick portion.

[0008] A fourth aspect of the present invention is the container according to the second or third aspect, wherein the first step portion and the second step portion are inclined with respect to the thickness direction of the side wall with the flat portion.

[0009] The invention of claim 5 is a container according to any one of claims 1 to 4, wherein the side walls are separated from the bottom and upper frame portion of the container, and are opposed to each other by being hinged at their upper and lower ends to the bottom and upper frame portion, and comprise a pair of first side walls that can be folded inward in half, and a pair of second side walls that are arranged between the pair of first side walls, have their upper ends hingedly connected to the upper frame portion, and can be folded upward and inward, and at least one of the pair of first side walls and the pair of second side walls is a side wall with a flat portion, and has a pair of outer edge protrusions at both lateral ends that extend in the vertical direction, form a groove-shaped cross section, and protrude outward.

[0010] In the invention of claim 6, of the first side walls, at least the lower first side wall of the upper first side wall and the lower first side wall that are folded in half and overlap each other is a side wall with the flat portion, and the back area of ​​the flat portion has the first thick portion, the second thick portion, and the third thick portion that is thicker than the first thick portion, and the protrusion side wall of the outer edge protrusion located on the third thick portion side is inclined with respect to the third thick portion, and the inner surface of the lower first side wall is provided with a curved portion that smoothly continues to the protrusion side wall and the third thick portion. Dependent on any one of claims 2 to 4 A container according to claim 5. [Effects of the Invention]

[0011] In the container of claim 1, a first step portion is formed in the back region of the flat portion of the outer surface of the side wall, and a first thick portion inside the first step portion is thicker than a second thick portion outside. In other words, in the container of claim 1, the inner portion of the side wall inside the outer edge is thickened to become the first thick portion, and the accompanying first step portion is formed on the inner surface of the side wall, so while providing a thick portion (first thick portion) to prevent warping, it is possible to eliminate the step portion that has been a problem in the past from the outer surface of the side wall, and it is possible to expand the area of ​​the outer surface of the side wall that can be used as an information display surface.

[0012] According to the configuration of claim 2, a second step portion is formed at a position closer to the outside of the first step portion, and a third thick portion having the same thickness as the first thick portion or thicker than the first thick portion is provided outside the second step portion, so that the progress of temperature drop of the resin is balanced across the entire flat portion of the side wall, and warping across the entire flat portion is suppressed.

[0013] The first and second step portions may be provided only at a pair of positions near the outer edges of the back region that face each other in the vertical direction or only at a pair of positions near the outer edges of the back region that face each other in the horizontal direction, or may be formed at positions near the outer edges of both the vertical and horizontal directions, with the first thick portion surrounded on all four sides by the second thick portion, and the second thick portion surrounded on all four sides by the third thick portion, as in the configuration of claim 3. In the configuration of claim 3, the first thick portion is surrounded on all four sides by the second thick portion, and the second thick portion is surrounded on all four sides by the third thick portion, thereby balancing the progress of temperature drop of the resin throughout the entire flat portion.

[0014] In the container of claim 4, the first step portion and the second step portion are inclined with respect to the thickness direction of the side wall with the flat portion, thereby preventing the luggage from getting caught and suppressing sudden changes in the thickness, thereby suppressing the occurrence of warping.

[0015] In a container according to claim 5, the side walls are separated from the bottom and upper frame, hinged at their upper and lower ends to the bottom and upper frame, and face each other. The side walls comprise a pair of first side walls that can be folded inward in half, and a pair of second side walls that are hinged at their upper ends to the upper frame. The pair of second side walls can be folded upward and inward, and then the pair of first side walls can be folded in half inward to bring the entire container into a folded state. Furthermore, since at least one of the pair of first side walls and the pair of second side walls has a flat portion and the container has the configuration of any one of claims 1 to 4, the outer surface of the pair of first side walls can be used as a wider information display surface than before.

[0016] In the container of claim 6, of the first side walls, the upper first side wall and the lower first side wall are folded in half to overlap each other, and at least the lower first side wall has a first thick portion, a second thick portion, and a third thick portion that is thicker than the first thick portion. This prevents the second side wall from getting caught on the first thick portion during rotation. In addition, the protruding side wall of the outer edge protrusion located on the third thick portion side is inclined with respect to the third thick portion, and the inner surface of the lower first side wall has a curved portion that smoothly connects the protruding side wall and the third thick portion. This also prevents the second side wall from getting caught on the third thick portion during rotation. This prevents a decrease in operability due to the thick portion (first thick portion) provided on the inner surface of the container to prevent warping. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a container according to an embodiment of the present disclosure. [Figure 2] A perspective view of the container in a folded state [Figure 3] 1 is a perspective view of a container with the second side wall partially folded; [Figure 4] 1 is a perspective view of a container with a first side wall partially folded; [Figure 5] 1 is a perspective view of the outer surface side of the first side wall; [Figure 6] A perspective view of the inner surface side of the first side wall [Figure 7] FIG. 1 is a perspective view of a first side wall with a partial cutaway; [Figure 8]A partially broken cross-sectional view of the first side wall [Figure 9] A cross-sectional side view of the upper end of the first side wall DETAILED DESCRIPTION OF THE INVENTION

[0018] A container 10A according to one embodiment of the present disclosure will be described below with reference to Figures 1 to 9. As shown in Figure 1, container 10A according to this embodiment has, for example, a rectangular parallelepiped shape in plan view, and is divided into a plurality of components which are movably connected to each other, so that it can be changed between an assembled state shown in the figure and a folded state shown in Figure 2.

[0019] Specifically, the container 10A is divided into a bottom 11, an upper frame 12, a pair of first side walls 20, a pair of second side walls 40, a pair of door lids 13, and a pair of sliders 14, and each first side wall 20 (corresponding to the "side wall with flat portion" in this disclosure) is further divided into an upper first side wall 21 and a lower first side wall 22. Furthermore, these multiple components of the container 10A are injection-molded resin products, and the entire container 10A is made of resin. The specific structure of each component will be described below.

[0020] As shown in Fig. 3, the bottom 11 has a structure in which a lower frame wall 11B stands up from the entire outer edge of a plate-shaped bottom wall 11A, and a plurality of hinge protrusions 11E are provided on the inner surface of a pair of long sides of the lower frame wall 11B. The lower surface of the bottom wall 11A is provided with ribs extending inward from the outer edge, forming lower surface protrusions 11T (see Fig. 4).

[0021] As shown in FIG. 4, the upper frame portion 12 includes an outer frame wall 12B, an inner frame wall 12C, and an upper wall 12A connecting the upper ends thereof. The cross section has a rectangular groove shape with an open bottom. The outer frame wall 12B is located directly above the lower frame wall 11B of the bottom portion 11, and when the upper frame portion 12 is in the folded state as shown in FIG. 2, the outer frame wall 12B and the lower frame wall 11B abut against each other. As shown in FIG. 4, the lower end of the inner frame wall 12C is located above the lower end of the outer frame wall 12B, and the lower ends of the inner frame walls 12C on a pair of short sides of the upper frame portion 12 are located above the lower ends of the inner frame walls 12C on a pair of long sides. A plurality of hinge protrusions 12E (see FIG. 3) are provided between the lower ends of the inner frame walls 12C on each side of the upper frame portion 12 and the inner surface of the outer frame wall 12B.

[0022] 1, a plurality of hinge protrusions 12F are provided on the upper surface of each of a pair of long sides of upper frame portion 12, and a pair of positioning protrusions 12D are provided on the upper surface of each of a pair of short sides of upper frame portion 12. Side recesses 12M, 12N are formed in the center of each of the pair of short sides and at both ends of each of the pair of long sides of upper frame portion 12, by recessing outer frame wall 12B and connecting it to inner frame wall 12C. At the upper end of side recess 12M, a portion of upper wall 12A remains as a handle 12L.

[0023] The pair of door lids 13 have hinge protrusions 13F at their base ends connected to hinge protrusions 12F of the upper frame 12, forming a so-called double door structure that opens and closes the top opening of the upper frame 12. When the door lids 13 are closed, the hinge protrusions 13F protrude upward from the main body 13H. The hinge protrusions 12F, 13F form positioning protrusions 12H on the top surfaces of the pair of long sides of the upper frame 12, and the positioning protrusions 12D on the top surfaces of the pair of short sides, allowing the bottom protrusions 11T (see FIG. 4) of another container 10A to fit inside the positioning protrusions 12H and 12D on the top surfaces of the pair of short sides of the upper frame 12.

[0024] As shown in Figure 2, the leading edges of the pair of door lids 13 are curved to form a point symmetry, with half of the leading edges forming protruding portions 13G that protrude toward the other, and the other half forming receiving portions 13J that receive the other protruding portion 13G. Receiving portion 13J is also provided with a lower surface overlapping portion (not shown) that overlaps the underside of the other protruding portion 13G. Sliders 14 slidably engage with the underside of each protruding portion 13G, and when each slider 14 is slid to the locked position, it engages with the other lower surface overlapping portion, locking the door lid 13 in the closed position.

[0025] As shown in Fig. 1, the pair of second side walls 40 have, at both lateral ends, a pair of outer edge projections 41 that extend vertically and protrude outward, forming a groove-shaped cross section. As shown in Fig. 3, the lower ends of the pair of outer edge projections 41 are connected by a pair of horizontal ribs 42A that protrude from the outer surface of the second side wall 40 and extend laterally, and the pair of horizontal ribs 42A are connected by a plurality of vertical ribs 42B. Although not shown, the upper ends of the pair of outer edge projections 41 are connected by a hinge support rib 26 that protrudes from the outer surface of the second side wall 40 and extends laterally, similar to the upper portion of the first side wall 20 described below (see Fig. 5), and the hinge support rib 26 has a plurality of hinge projections 21E on its upper surface. The multiple hinge protrusions 21E of each second side wall 40 engage with the aforementioned hinge protrusions 12E of each short side portion of the upper frame portion 12, so that the upper end of the second side wall 40 is hinge-connected (rotatably connected) to the upper frame portion 12.

[0026] 3, a pair of locking claws 44 for attaching a card holder protrude from both sides of the lower end of the outer surface of the second side wall 40. Furthermore, a pair of receiving recesses 43A are formed in the vertical middle of each outer edge protrusion 41 of the second side wall 40. The receiving recesses 43A open on the outer surface and the tip surface of the outer edge protrusion 41, and a protrusion 43B protrudes slightly from the opening edge of the receiving recess 43A on the outer surface side of the outer edge protrusion 41.

[0027] 5, the pair of first side walls 20 are divided into an upper first side wall 21 and a lower first side wall 22 at the vertical middle, which are hingedly connected together. Both the upper first side wall 21 and the lower first side wall 22 have a pair of outer edge projections 23 at both lateral ends, which have a groove-shaped cross section, extend vertically, and project outward.

[0028] The upper ends of the pair of outer edge protrusions 23 of the upper first side wall 21 are connected by a hinge support rib 26 that protrudes from the outer surface of the upper first side wall 21 and extends laterally, and a plurality of hinge protrusions 21E are provided on the upper surface of the hinge support rib 26. These hinge support ribs 26 have a slightly meandering shape in the vertical direction to correspond to the plurality of hinge protrusions 21E, 22E. In addition, the lower ends of the pair of outer edge protrusions 23 of the lower first side wall 22 are also connected by the hinge support rib 26, and a plurality of hinge protrusions 22E are provided on the lower surface of the hinge support rib 26. The multiple hinge protrusions 21E of the upper first side wall 21 engage with the aforementioned hinge protrusions 12E on each long side portion of the upper frame portion 12, so that the upper end portion of the first side wall 20 is hingedly connected to the upper frame portion 12, and the multiple hinge protrusions 22E of the lower first side wall 22 engage with the aforementioned hinge protrusions 11E on each long side portion of the bottom portion 11, so that the lower end portion of the first side wall 20 is hingedly connected to the bottom portion 11.

[0029] The lower ends of the pair of outer edge protrusions 23 of the upper first side wall 21 are connected by a pair of horizontal ribs 25 (see FIG. 4) that protrude from the outer surface of the upper first side wall 21 and extend laterally, and the pair of horizontal ribs 25 are provided with a plurality of hinge protrusions 21F shown in FIG. 5 at multiple locations in the longitudinal direction. On the other hand, the upper ends of the pair of outer edge protrusions 23 of the lower first side wall 22 are connected by an outer edge protrusion 24 that has a groove-shaped cross section, extends laterally, and protrudes outward, and the upper surface of the outer edge protrusion 24 is provided with a plurality of hinge protrusions 22F shown in FIG. 5 at multiple locations. The plurality of hinge protrusions 21E at the lower end of the upper first side wall 21 engage with the plurality of hinge protrusions 21F at the upper end of the lower first side wall 22, thereby hinge-connecting the upper first side wall 21 and the lower first side wall 22.

[0030] As shown in FIG. 6 , the upper first side wall 21 and the lower first side wall 22 are provided with a partition rib 28 that horizontally divides the interior of each outer edge protrusion 23 into two. The partition rib 28 is located laterally outward of the outer edge protrusion 23. A side through-hole 29A that penetrates the tip wall 23A of the outer edge protrusion 23 is formed in a region of the outer edge protrusion 23 outside the partition rib 28, closer to the center of the first side wall 20 in the up-down direction. A pair of horizontal ribs 28A are provided on the upper and lower opening edges of the side through-hole 29A, connecting the partition rib 28 with the outer protrusion side wall 23D of the outer edge protrusion 23. An engagement piece 29 is provided on the opening edge of the side through-hole 29A opposite the partition rib 28, extending from a portion of the protrusion side wall 23D and bent at a right angle toward the partition rib 28. When container 10A is in the assembled state, engaging piece 29 is received in receiving recess 43A of second side wall 40, connecting second side wall 40 and first side wall 20. With the above configuration, container 10A can be switched between the assembled state and the folded state, as described above.

[0031] The first side wall 20 and the second side wall 40 are reinforced by an outer edge reinforcement portion consisting of a hinge support rib 26, a horizontal rib 42A, and outer edge protrusions 23, 24, and 41 that protrude from the main plate portions 30 and 49, which are the primary plate portions of the first side wall 20 and the second side wall 40. While some containers have ribs or groove-shaped structures on the inner side of the outer edge reinforcement portion, the container 10A of this embodiment does not have ribs or groove-shaped structures on the inner side of the outer edge reinforcement portion of the first side wall 20 and the second side wall 40. In the second side wall 40, a rectangular region of the main plate portion 49 that is surrounded by the outer edge reinforcement portion consisting of the outer edge protrusion 41, the horizontal rib 42A, and the hinge support rib 26 is slightly thickened outward to form a thickened portion 45. This thickened portion 45 suppresses warping of the second side wall 40. The thick portion 45 also serves as a back rest for the card holder attached to the pair of locking claws 44.

[0032] The mechanism by which warpage is suppressed by providing the thickened portion 45 in the second side wall 40 is believed to be as follows. Specifically, if the portion of the main plate portion 49 of the second side wall 40 surrounded by the outer edge reinforcement is a flat plate of uniform thickness, the outer edge region of the flat plate cools more easily than the inner region and shrinks more than the inner region. Therefore, the outer edge region hardens and shrinks before the inner region. The central region cannot absorb this shrinkage, and the resin in the central region bulges and hardens without an escape route, resulting in warpage. Furthermore, if the flat plate does not have a uniform thickness, the thicker portion shrinks more than the thinner portion. Therefore, by providing the thickened portion 45 as in the second side wall 40 of this embodiment, the inner region of the portion of the second side wall 40 surrounded by the outer edge reinforcement can shrink more than the outer region, thereby suppressing the bulging of the resin in the central region and suppressing warpage, compared to when the thicknesses are uniform.

[0033] As shown in FIG. 6 , the upper first side wall 21 and the lower first side wall 22 have first thick portions 31 corresponding to the thick portions 45 of the second side wall 40, protruding inward. As shown in FIG. 5 , in the upper first side wall 21 and the lower first side wall 22, the outer surface of the main plate portion 30, which is surrounded by an outer edge reinforcement portion including the outer edge protrusions 23, the horizontal ribs 25, the outer edge protrusions 24, the hinge support ribs 26, etc., forms a flat portion 39 without any irregularities. Hereinafter, to clarify that the flat portion 39 is the outer surface flat portion 39, not the inner surface of the upper first side wall 21 and the lower first side wall 22, the flat portion 39 will be referred to as the “outer surface flat portion 39,” and the region behind the outer surface flat portion 39 will be referred to as the “rear region 39R,” and the structure of the upper first side wall 21 and the lower first side wall 22 will be described in detail.

[0034] As shown in FIG. 6, a first step portion 31S and a second step portion 33S are formed near the outer edge of the rear region 39R of the upper first side wall 21. The first step portion 31S and the second step portion 33S form similar quadrangles, with the first step portion 31S located inside the second step portion 33S. As shown in FIGS. 7 and 8, a recess is formed between the first step portion 31S and the second step portion 33S, and the first thick portion 31 located inside the first step portion 31S is thicker than the second thick portion 32 located between the first step portion 31S and the second step portion 33S. Furthermore, the third thick portion 33 located outside the second step portion 33S in the rear region 39R is thicker than the first thick portion 31, and the inner surface of the third thick portion 33 is located closer to the interior of the container 10A than the inner surface of the first thick portion 31. The first step portion 31S and the second step portion 33S are gently inclined relative to the inner surface of the second thick portion 32.

[0035] 8, on both sides of the upper first side wall 21, the protrusion side walls 23B of the outer edge protrusion 23 are inclined with respect to the thickness direction of the main plate portion 30. An arc-shaped curved portion 33K is provided that smoothly connects the inner surface of the protrusion side wall 23B with the third thick portion 33. Also, at both upper and lower ends of the upper first side wall 21, the hinge support ribs 26 and the lateral ribs 25 protrude perpendicularly from the third thick portion 33, as shown in FIGS. 4 and 9. The wall thicknesses of the outer edge protrusion 23, the lateral ribs 25, the outer edge protrusion 24, the hinge support rib 26, etc. are close to those of the first thick portion 31 or the third thick portion 33.

[0036] The back side of the outer flat portion 39 of the lower first side wall 22 is similar to that of the upper first side wall 21. Furthermore, with regard to the upper end portion of the lower first side wall 22, the protruding portion side wall 24B of the outer edge protrusion 24 stands vertically from the third thick portion 33 as shown in FIG.

[0037] This completes the description of the configuration of container 10A of this embodiment. Next, the effects of container 10A will be described. In container 10A of this embodiment, the inner surfaces of upper first side wall 21 and lower first side wall 22 are thickened from the outer edges to form first thick portions 31, and the associated first step portions 31S are formed on the inner surfaces. Therefore, while providing thick portions (first thick portions 31) for preventing warping, the associated step portions (first step portions 31S) can be eliminated from the outer surfaces, and the area of ​​the outer surfaces of upper first side wall 21 and lower first side wall 22 that can be used as an information display surface can be expanded.

[0038] Furthermore, by surrounding the second thick portion 32, which is thinner and located outside the first thick portion 31, with the third thick portion 33, which is thicker, the progress of temperature drop of the resin is balanced across the entire outer flat portion 39 of the upper first side wall 21 and the lower first side wall 22, effectively suppressing warping across the entire outer flat portion 39. Moreover, because the third thick portion 33 is thicker than the first thick portion 31 and protrudes further inward than the first thick portion 31 into the container 10A (see FIG. 8), the second side wall 40 is prevented from getting caught on the first thick portion 31 during rotation. Furthermore, protrusion side wall 23B of outer edge protrusion 23 located on the third thick portion 33 side is inclined relative to third thick portion 33, and the inner surfaces of upper first side wall 21 and lower first side wall 22 are provided with curved portions 33K that smoothly connect protrusion side wall 23B and third thick portion 33. This also prevents second side wall 40 from getting caught on third thick portion 33 during rotation. These prevent a decrease in operability when folding and assembling container 10A due to the provision of a thick portion (first thick portion 31) on the inner surface of container 10A to prevent warping.

[0039] Furthermore, the first step portion 31S and the second step portion 33S are inclined with respect to the thickness direction of the upper first side wall 21 and the lower first side wall 22, which prevents luggage from getting caught and also suppresses sudden changes in thickness, thereby suppressing warping.

[0040] [Other embodiments] (1) In the container 10A of the above embodiment, the third thick portion 33 is formed on the outside of the second thick portion 32, but the third thick portion 33 may not be provided.

[0041] (2) In the container 10A of the above embodiment, the first thick portion 31 is surrounded on all four sides by the first step portions 31S. However, the first step portions 31S may be provided only near the outer edges of either the top-bottom or bottom-bottom ends of the upper first side wall 21 or the lower first side wall 22, with the space therebetween being the first thick portion 31. The same applies to the second step portions 33S. However, a configuration in which the first thick portion 31 is surrounded on all four sides by the second thick portions 32, and the second thick portion 32 is surrounded on all four sides by the third thick portions 33, as in the above embodiment, is preferable because it allows the temperature drop of the resin in the entire outer surface flat portion 39 to proceed in a more balanced manner.

[0042] (3) In the container 10A of the above embodiment, the first step portion 31S and the second step portion 33S are rectangular, but they may be circular or elliptical.

[0043] (4) The container 10A in the above embodiment is a foldable container, but the first thick portion 31, the second thick portion 32, the third thick portion 33, etc. may be provided on the inner surface of the side wall of a non-foldable container. Also, the first thick portion 31, the second thick portion 32, the third thick portion 33, etc. may be provided on the lid or the bottom wall.

[0044] (5) In the above embodiment, the first step portion 31S and the second step portion 33S are inclined with respect to the thickness direction of the first side wall 20. However, they may be parallel to the thickness direction.

[0045] 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]

[0046] 10A container 11 Bottom 12 Upper frame 20 First side wall (side wall with flat section) 21 Upper first side wall (side wall with flat portion) 22 Lower first side wall (side wall with flat portion) 23 Outer edge protrusion 23B Projection side wall 31 1st thick part 31S First step 32 2nd thick part 33 Third thick part 33S 2nd step 33K curved section 39 Flat area 39R back area 40 Second side wall

Claims

1. In a resin container, a plurality of side walls include a flat side wall in which the flat portion has no reinforcing rib inside the outer edge of the outer surface, A container in which a first step portion is formed near a pair of opposing outer edges in the back region of the flat portion, and a first thick portion inside the first step portion is thicker than a second thick portion outside the first step portion.

2. A container as described in claim 1, wherein a second step portion is formed in the rear region at a position closer to the outside than the first step portion, and a third thick portion having the same thickness as the first thick portion or thicker than the first thick portion is provided outside the second step portion in the rear region.

3. The container described in claim 2, wherein the first step portion and the second step portion are formed near the outer edges in the vertical and horizontal directions, and the first thick portion is surrounded on all four sides by the second thick portion, and the second thick portion is surrounded on all four sides by the third thick portion.

4. The container according to claim 2 or 3, wherein the first step portion and the second step portion are inclined with respect to the thickness direction of the side wall with the flat portion.

5. The plurality of side walls are separated from an upper frame portion which is a bottom portion and an upper portion of the container, and are composed of a pair of first side walls which are opposed to each other by being hingedly connected at their upper and lower ends to the bottom portion and the upper frame portion and can be folded inward in two, and a pair of second side walls which are disposed between the pair of first side walls and have their upper ends hingedly connected to the upper frame portion and can be folded upward and inward, 5. A container according to claim 1, wherein at least one of the pair of first side walls and the pair of second side walls is a side wall with a flat portion, and has a pair of outer edge protrusions at both lateral ends, which have a groove-shaped cross section, extend in the vertical direction, and protrude outward.

6. Among the first side walls, at least the lower first side wall out of the upper first side wall and the lower first side wall that are folded in half and overlap each other is the side wall with the flat portion, and has the first thick portion, the second thick portion, and the third thick portion that is thicker than the first thick portion in the back region of the flat portion, A container as described in claim 5, which is dependent on any one of claims 2 to 4, wherein the protrusion side wall of the outer edge protrusion located on the side of the third thick portion is inclined with respect to the third thick portion, and the inner surface of the lower first side wall is provided with a curved portion that smoothly connects the protrusion side wall and the third thick portion.

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