Tray-shaped container

Abstract

To provide a tray-like container made of paper with a bottom plate and side plates, which is easy to fold and has excellent shape retention and does not require incision lines.SOLUTION: A try-like container 1 of the invention comprises: a polygonal bottom plate 2 having alternately a first side 5A whose length is greater than or equal to the length of each of the adjacent sides and a second side 5B whose length is less than or equal to the length of each of the adjacent sides; a first side plate 3A connected to the bottom plate 2 via a valley fold line 7A; a second side plate 3B connected to the bottom plate 2 via a valley fold line 7B; and a connecting piece 4 with a ridge fold line and interposed between the first side plate 3A and the second side plate 3B. The connecting piece 4 is connected to the first side plate 3A via the bending guide line 10 and to the second side plate 3B via the valley fold line. The ridge fold line and the valley fold line between the connecting piece 4 and the second side plate 3B originate at the top of the polygon and extend to the outer edge 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tray-like container. [Background technology]

[0002] Conventionally, paper tray-shaped containers used for packaging and transporting food and the like have been known. For example, the tray-shaped container disclosed in Patent Document 1 is assembled into a tray shape by folding the side panels from a blank sheet having a bottom panel and side panels. This tray-shaped container is characterized in that, in order to reduce processing costs, the folding is not performed by press molding and no adhesive is required for folding. Here, ear-shaped protrusions formed by cutting lines into the blank sheet contribute to improved shape retention. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6254340 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the tray-shaped container disclosed in Patent Document 1 has the risk of liquid leaking from the placed object leaking through the cut lines, and paper dust being generated when the cut lines are formed. Furthermore, before shipping the tray-shaped container (or its blank sheet), it is necessary to inspect whether the cut lines are properly formed.

[0005] Therefore, the object of the present invention is to provide a paper tray-like container having a bottom plate and side plates, which is easy to fold and has excellent shape retention, but does not require cut lines. [Means for solving the problem]

[0006] The present invention provides a paper tray-like container comprising: a polygonal bottom plate having alternating first sides whose lengths are equal to or greater than the lengths of the adjacent sides on either side and second sides whose lengths are equal to or less than the lengths of the adjacent sides on either side; a first side plate connected to the bottom plate at the first side via a valley fold line; a second side plate connected to the bottom plate at the second side via the valley fold line; and a connecting piece having a mountain fold line and interposed between the first side plate and the second side plate, wherein the connecting piece is connected to the first side plate via a bending guide line and to the second side plate via the valley fold line, and the mountain fold line and the valley fold line between the connecting piece and the second side plate extend from a vertex of the polygon to the outer periphery.

[0007] This tray-shaped container does not have any cut lines for folding or shape retention. Instead, the first and second side panels are folded by the valley fold lines between the bottom panel and the first side panel, the valley fold lines between the bottom panel and the second side panel, the mountain fold lines in the connecting piece, and the valley fold lines between the connecting piece and the second side panel. The first side panel and the connecting piece are bent to form a curved surface around the bending guide lines, thereby maintaining the overall tray shape. This folding can be performed manually or by press molding. During press molding, the first side panel or the connecting piece is bent to form a curved surface around the bending guide lines, so that the folded portions formed by the mountain fold lines in the connecting piece and the valley fold lines between the connecting piece and the second side panel are pressed in a state away from the bending guide lines. In other words, if the blank sheet has the various lines described above, it will naturally assume a shape suitable for shape retention in a press molding machine.

[0008] In this tray-shaped container, the valley fold line on the first side and the valley fold line on the second side may include a half-slit line on the back side. This makes it easier to fold the side panels. Furthermore, by providing the half-slit line on the back side rather than the front side, it is possible to avoid the problem of liquid leaking from placed items seeping in, which occurs when the half-slit line is provided on the front side.

[0009] It is preferable that the half-slit lines are discontinuous at the vertices of the polygon. If the half-slit lines are continuous at the vertices of the polygon, the paper is more likely to delaminate at those points. Therefore, by making the half-slit lines discontinuous at the vertices of the polygon, the discontinuous points act as joints, preventing delamination of the paper.

[0010] The angle formed by the valley fold line between the connecting piece and the second side panel and the second edge is preferably less than 90°. This allows the shape of the second side panel to be close to a trapezoid with an acute base angle, making it possible to better maintain the folded shape.

[0011] It is preferable that the portion of the connecting piece that forms the outer periphery of the tray-shaped container is curved, which makes it possible to prevent the wrap from tearing when the tray-shaped container and the placed object are covered with wrap.

[0012] The polygon formed by the bottom plate may be a polygon in which all interior angles are equal. The first sides may be made up of a plurality of sides with different lengths. At least one of the first sides may have a length ratio to the length of the second side of 4 to 8. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a tray-shaped container made of paper having a bottom plate and side plates, which is easy to fold and has excellent shape retention, but does not require cut lines. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of a tray-shaped container according to one embodiment of the present invention. [Figure 2] 2 is a plan view of a blank sheet before being made into the tray-shaped container of FIG. 1. FIG. [Figure 3] 3A is a plan view showing a part of FIG. 2, and FIG. 3B is a cross-sectional view taken along line IIIB-IIIB of FIG. 3A. [Figure 4] This is how the part shown in Figure 3 looks folded up. [Figure 5] FIG. 3 is a partial view of the blank sheet of FIG. 2 at the moment when the blank sheet is pressed by a press molding machine. [Figure 6] FIG. 10 is a cross-sectional view of a modified example of the blank sheet. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will be omitted.

[0016] The tray-shaped container of this embodiment is used for packaging and transporting food or the like. A sheet of paper punched into a predetermined shape from base paper and having folding lines formed thereon by a press or the like is called a "blank sheet." The terms "valley fold line" and "mountain fold line" used in the following description refer to the folding direction when the tray-shaped container or blank sheet is viewed from the front. "Front" refers to the surface on which food or the like is placed. The terms "valley fold line" and "mountain fold line" are used both before and after folding. In the following description, when referring to shapes such as "octagon" and "isosceles trapezoid," the term "side" refers to the shape observed when the blank sheet is viewed in plan. In addition, the portions indicated by dashed lines in the drawings refer to folding lines and stepped portions of the paper.

[0017] 1 and 2, the tray-shaped container 1 of this embodiment is formed by folding portions of a single paper blank sheet 100. The tray-shaped container 1 includes a bottom plate 2 that is octagonal in plan view, first side plates 3A connected to the bottom plate 2 on all four sides, and second side plates 3B connected to the bottom plate 2 on the other four sides. The tray-shaped container 1 further includes a connecting piece 4 interposed between the first side plate 3A and the second side plate 3B. The bottom plate 2, first side plate 3A, second side plate 3B, and connecting piece 4 are connected to one another without any gaps, and the outer periphery 8 of the blank sheet 100 has a substantially octagonal shape.

[0018] The octagon forming the bottom plate 2 has two equal interior angles and four pairs of opposite sides that are parallel. This octagon has two different side lengths. That is, it alternates between first sides 5A whose lengths are equal to or greater than the lengths of the adjacent sides and second sides 5B whose lengths are equal to or less than the lengths of the adjacent sides. In other words, the octagon alternates between first sides 5A of a certain length and second sides 5B whose lengths are equal to or less than the lengths of the first sides 5A. In yet other words, the octagon has first sides 5A whose lengths are equal to or greater than a predetermined length and second sides 5B whose lengths are equal to or less than a predetermined length. There are four first sides 5A and four second sides 5B, and all four first sides 5A are the same length, and all four second sides 5B are the same length.

[0019] As for specific dimensions, first side 5A may be, for example, 10 cm to 50 cm, or 15 cm to 45 cm. Second side 5B may be, for example, 1 cm to 10 cm, or 2 cm to 5 cm. The ratio of the length of first side 5A to the length of second side 5B may be 4 to 8.

[0020] The first side panel 3A is connected to the bottom panel 2 at the first edge 5A via a valley fold line 7A, and the second side panel 3B is connected to the bottom panel 2 at the second edge 5B via a valley fold line 7B. These valley fold lines 7A, 7B form half-slit lines on the back surface of the tray-shaped container 1 and the blank sheet 100. Here, "half-slit lines" refer to lines that cut approximately halfway through the thickness of the paper. These half-slit lines are discontinuous at the vertices of the octagonal shape of the bottom panel 2. In other words, the number of half-slit lines is the same as the number of sides of the polygonal shape of the bottom panel 2, and they exist as independent straight lines. Where the half-slit lines are discontinuous, the distance between the ends of adjacent half-slit lines is preferably 5 mm or less, for example, 3 mm or less, 2 mm or less, or 1 mm or less.

[0021] The first side panel 3A and the second side panel 3B have the same width. Here, the "width" of the first side panel 3A or the second side panel 3B refers to the dimension of the first side panel 3A or the second side panel 3B in the direction perpendicular to the first side 5A or the second side 5B of the blank sheet 100. The width of the first side panel 3A or the second side panel 3B may be 3% to 15% or 5% to 10% of the overall dimension of the blank sheet 100, including the two first side panels 3A or the two second side panels 3B facing each other across the bottom panel 2. Considering that the blank sheet 100 will be molded into the tray-shaped container 1 using a press molding machine described below, the specific width of the first side panel 3A and the second side panel 3B may be 5 mm to 30 mm or 10 mm to 20 mm, regardless of the size of the bottom panel 2.

[0022] 3(A) and 4, the connecting pieces 4 are parts that connect the first side plate 3A and the second side plate 3B, and are present at a total of eight locations on the tray-shaped container 1 and the blank sheet 100. In the blank sheet 100, the connecting pieces 4 also serve to form part of the outer peripheral edge 8 of the blank sheet 100, connecting the edge of the first side plate 3A and the edge of the second side plate 3B in a curved line.

[0023] The connecting piece 4 has a mountain fold line 9C extending from the center of the blank sheet 100 toward the outside at its approximate center, and is connected to the second side panel 3B via a valley fold line 7C. The connecting piece 4 is also connected to the first side panel 3A via a bending guide line 10. Here, as shown in FIG. 3(B), the "mountain fold line 9C" and the "valley fold line 7C" refer to lines that have a linear convex portion with a certain width when viewed from one of the front and back surfaces, and a concave portion when viewed from the other surface, and are intended to fold the paper at that portion. The "bending guide line 10" refers to a step in the paper that is not intended to fold the paper at that portion. In this embodiment, the bending guide line 10 is provided with a step so that the connecting piece 4 side is higher and the first side panel 3A side is lower when viewed from the front surface of the blank sheet 100. The bending guide lines 10 do not necessarily bend the tray-shaped container 1, but are lines that guide the direction in which the peaks of the folded-back portions 12, which will be described later, protrude. These lines can be formed, for example, by a press.

[0024] The mountain fold lines 9C and the valley fold lines 7C start from the vertices of the bottom plate 2 and extend to the outer peripheral edge 8 of the tray-shaped container 1. The bending guide lines 10 also start from the vertices and extend to the outer peripheral edge 8 of the tray-shaped container 1. In other words, in the tray-shaped container 1 and the blank sheet 100, the mountain fold lines 9C, the valley fold lines 7C, and the bending guide lines 10 start from one of the vertices of the bottom plate 2 and extend radially toward the outer peripheral edge nearby.

[0025] In this embodiment, the angles formed by the second side 5B and the two adjacent valley fold lines 7C sandwiching the second side panel 3B are equal to each other and less than 90°. That is, the second side panel 3B forms an isosceles trapezoid with all base angles being acute. The angles may be 40° to 89°, 50° to 85°, or 60° to 80°.

[0026] As shown in Figure 4, when the valley fold lines 7A, 7B, and 7C and the mountain fold line 9C are all folded (i.e., the tray-shaped container 1), a folded portion 12 is formed with the mountain fold line 9C as its apex when viewed from the inside of the front surface of the tray-shaped container 1. Two adjacent folded portions 12, 12 sandwiched between the second side panel 3B are inclined so that the apexes of their mountain folds face each other. In other words, two adjacent folded portions 12, 12 sandwiched between the second side panel 3B are both inclined so that they face away from each mountain fold line 9C and each bending guide line 10 adjacent to each first side panel 3A. In this state, the bending guide lines 10 are not folded.

[0027] In the tray-shaped container 1, the folded angle of the first side panel 3A (the angle formed between the bottom panel 2 and the first side panel 3A) may be 100° to 160°, 110° to 150°, or 120° to 140°.

[0028] The paper used for the tray-shaped container 1 should be of a quality that provides the rigidity and shape retention required for functioning as a tray. Examples of the type of paper include general paperboard, such as double-sided cardboard, manila cardboard, white-backed cardboard, cup base paper, and ivory paper. Paper that is water-resistant and oil-resistant is preferred, and paperboard with a resin such as polyethylene laminated on its surface is preferred. The paper may be single-layered or multi-layered. The paper should have a basis weight of 160 g / m². 2 ~550g / m 2 The thickness of the paper may be 1.0 mm or less, or may be 0.8 mm or less.

[0029] The process of folding each portion of the blank sheet 100 to form the tray-shaped container 1 may be performed manually, or may be performed using a press molding machine as shown in Figure 5. The press molding method involves preparing a female mold 20 that has approximately the same shape as the bottom plate 2 and has a hole with a slightly larger area than the bottom plate 2. The blank sheet 100 is placed on top of the hole. Then, it is pressed using a male mold 30 that has approximately the same shape as the bottom plate 2 and a slightly smaller area than the bottom plate 2.

[0030] FIG. 5 shows the state of the blank sheet 100 at the moment it is pressed. The pressed blank sheet 100 fits into the clearance (gap) 40 between the female die 20 and the male die 30 in the shape of a tray-shaped container 1. Here, the valley fold lines 7A, 7B, 7C and the mountain fold line 9C are all bent, and the two adjacent folds 12, 12 on both sides of the second side panel 3B are inclined so that the peaks of their mountain folds face each other. At the same time, one of the two surfaces that make up the mountain fold faces the second side panel 3B, and the other of the two surfaces faces the male die 30. Here, the portion of the bending guide line 10 is not bent.

[0031] After pressing, the molded tray-shaped container 1 is obtained by removing it from the male mold 30 and the female mold 20.

[0032] The tray-shaped container 1 thus formed manually or by a press molding machine does not have any cut lines for folding or maintaining the shape, and the first side panel 3A and the second side panel 3B are folded together by the valley fold line 7A between the bottom panel 2 and the first side panel 3A, the valley fold line 7B between the bottom panel 2 and the second side panel 3B, the mountain fold line 9C of the connecting piece 4, and the valley fold line 7C between the connecting piece 4 and the second side panel 3B, and the tray shape is maintained as a whole by the first side panel 3A and the connecting piece 4 bending to form a curved surface around the bending guide line 10. In particular, when forming by press molding, the first side panel 3A and the connecting piece 4 bending to form a continuous curved surface around the bending guide line 10 allows the folded portion 12 to be pressed in a state facing away from the bending guide line 10. In other words, if the blank sheet 100 has the various lines described above, the presence of the bending guide line 10 will properly guide the direction in which the folded portion 12 faces, and the tray-shaped container 1 will take on the desired shape inside the press molding machine.

[0033] As described above, the tray-shaped container 1 of this embodiment can be easily formed into a tray shape and has sufficient shape retention without processing and molding such as cutting cut lines for assembly. Because the tray-shaped container 1 does not have cut lines, leakage of liquid leaked from placed items (for example, condensation water or drips from fresh food) is prevented, and the risk of paper dust being generated during shape processing is reduced.

[0034] Furthermore, in the tray-shaped container 1, half-slit lines are provided on the backside of the valley fold lines 7A, 7B, making it easier to fold the first side panel 3A and the second side panel 3B. Also, by providing the half-slit lines on the backside instead of the front side, it is possible to avoid the problem of liquid seeping in from the contents that leaks out when the half-slit lines are provided on the front side. Furthermore, because the half-slit lines are discontinuous at the apex of the bottom panel 2, the discontinuous areas act as joints to prevent delamination of the paper layers.

[0035] Furthermore, in the tray-shaped container 1, the second side panel 3B has an isosceles trapezoidal shape, which contributes to maintaining the folded shape. This shape also makes it easier for the second side panel 3B to be folded toward the inside of the tray-shaped container 1.

[0036] Furthermore, in the tray-shaped container 1, the connecting pieces 4 have a curved shape that forms the outer edge 8 of the tray-shaped container 1, which prevents the wrap from tearing when the tray-shaped container 1 and the placed items are covered or wrapped in plastic wrap. In addition, because the tray-shaped container 1 is made of paper and is formed only by folding, it is flexible when the tray-shaped container 1 and the placed items are covered or wrapped in plastic wrap, and can easily follow the tension of the plastic wrap.

[0037] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, in the above embodiments, the first sides 5A are all the same length, but the first sides 5A may be made up of a plurality of sides with different lengths. For example, in the blank sheet 100 shown in FIG. 2, the lengths of a pair of opposing first sides 5A may be changed within a range of 50% to 300% or within a range of 80% to 200%.

[0038] In the above embodiment, the first side plate 3A and the second side plate 3B have the same width, but they may have different widths. Furthermore, the shapes of the first side plate 3A and the second side plate 3B may be changed so that the outer periphery 8 of either the first side plate 3A or the second side plate 3B has a shape other than a straight line.

[0039] Furthermore, in the above embodiment, the bending guide wire 10 has a step so that the connecting piece 4 side is higher and the first side plate 3A side is lower when viewed from the surface of the blank sheet 100, but conversely, the bending guide wire 10 may have a step so that the connecting piece 4 side is lower and the first side plate 3A side is higher when viewed from the surface of the blank sheet 100.

[0040] In the above embodiment, the mountain fold lines 9C and the valley fold lines 7C are ruled lines having linear convex and concave portions, respectively, when viewed from the front side of the blank sheet 100 (FIG. 3(B)). However, the mountain fold lines 9C' may be concave and the valley fold lines 7C' may be convex, as shown in FIG. 6. Even in this case, the folding direction remains the same.

[0041] In the above embodiment, the bending guide line 10 starts from the vertex of the bottom plate 2, but other configurations are possible as long as they can properly guide the direction of the folded portion 12. For example, the starting point may be a position on the first side 5A that is within 1 cm or 2 cm from the vertex of the bottom plate 2.

[0042] In addition, although the above embodiment shows an aspect in which the bottom plate 2 is octagonal, the bottom plate 2 may be other polygonal shapes such as a hexagon or a decagon. From the viewpoint of symmetry of the shape, it is preferable that the number of sides of the bottom plate is an even number. [Industrial Applicability]

[0043] The present invention can be used, for example, in packaging food products. [Explanation of symbols]

[0044] 1...tray-shaped container, 2...bottom plate, 3A...first side plate, 3B...second side plate, 4...connecting piece, 5A...first edge, 5B...second edge, 7A, 7B, 7C, 7C'...valley fold line, 8...outer edge, 9C, 9C'...mountain fold line, 10...bending guide line, 12...folded portion, 20...female mold, 30...male mold, 100...blank sheet.

Claims

1. a polygonal bottom plate having alternating first sides whose lengths are equal to or greater than the lengths of the adjacent sides and second sides whose lengths are equal to or less than the lengths of the adjacent sides; a first side plate connected to the bottom plate via a valley fold line on the first side; a second side plate connected to the bottom plate via a valley fold line on the second side; a connecting piece having a mountain fold line and interposed between the first side plate and the second side plate, The connecting piece is connected to the first side plate via a bending guide line and is connected to the second side plate via a valley fold line, the mountain fold line and the valley fold line between the connecting piece and the second side plate extend from a vertex of the polygon to an outer periphery, When the valley fold lines and the mountain fold lines are all folded, a folded portion is formed with the mountain fold lines as vertices, The folded portion is visible when viewed from the front surface side of the bottom plate, A paper tray-like container, wherein the angle formed by the valley fold line between the connecting piece and the second side panel and the second side is less than 90°.

2. The tray-shaped container according to claim 1 , wherein the valley fold line on the first side and the valley fold line on the second side include a half-cut line provided on the back surface.

3. 3. The tray-like container according to claim 2, wherein the half-cut lines are discontinuous at the vertices of the polygon.

4. A polygonal base plate having alternating first sides whose lengths are equal to or greater than the lengths of the adjacent sides and second sides whose lengths are equal to or less than the lengths of the adjacent sides; a first side plate connected to the bottom plate via a valley fold line on the first side; a second side plate connected to the bottom plate via a valley fold line on the second side; a connecting piece having a mountain fold line and interposed between the first side plate and the second side plate, The connecting piece is connected to the first side plate via a bending guide line and is connected to the second side plate via a valley fold line, the mountain fold line and the valley fold line between the connecting piece and the second side plate extend from a vertex of the polygon to an outer periphery, When the valley fold lines and the mountain fold lines are all folded, a folded portion is formed with the mountain fold lines as vertices, The folded portion is visible when viewed from the front surface side of the bottom plate, the valley fold line on the first side and the valley fold line on the second side include a half-cut line provided on the back surface, A paper tray-like container, wherein the half-cut lines are discontinuous at the vertices of the polygon.

5. 5. The tray-shaped container according to claim 1, wherein the connecting piece has a curved portion that forms the outer periphery of the tray-shaped container.

6. 6. The tray-shaped container according to claim 1, wherein the polygon has all equal interior angles.

7. The tray-shaped container according to any one of claims 1 to 6, wherein the first side comprises a plurality of sides having different lengths.

8. 8. The tray-shaped container according to claim 1, wherein at least one of the first sides has a length ratio to the length of the second side of 4 to 8.

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