JP7597166B2 - Blank Sheets and Trays - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act On August 29, 2019, Moriha Paper Co., Ltd. sold blank sheets for trays related to the invention to Sato Farm Ltd.

The present invention relates to a blank sheet and a tray.

Some cardboard trays have crosspieces connected to the upper edges of the front and rear end walls, and engagement slits extending laterally are formed in the left and right side walls, with the lower parts of engagement pieces connected to the crosspieces being inserted into the engagement slits from the outside (see, for example, Patent Document 1).

Japanese Utility Model Application Publication No. 6-25135

In the process of assembling the conventional tray described above, when inserting the engagement piece into the engagement slit, the engagement slit is in a closed state, making it difficult to insert the engagement piece into the engagement slit.

SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a blank sheet and a tray that can solve the above-mentioned problems and improve the work efficiency during assembly.

In order to solve the above problems, the present invention provides a tray or a blank sheet for forming the tray, the tray comprising a bottom plate, front and rear end walls and left and right side walls connected to the bottom plate, and an inner flap connected to the front and rear edges of the side walls and overlapped on the inner surface of the end walls. The tray also comprises a batten connected to the upper edge of the end wall and an engagement piece connected to the left and right edges of the batten. An engagement slit is formed extending laterally from the side wall to the inner flap, and a lower part of the engagement piece is inserted into the engagement slit from the outside. The upper part of the side wall and the upper part of the inner flap are connected via an upper fold line. The lower part of the side wall and the lower part of the inner flap are connected via two lower fold lines. The horizontal distance between the two lower fold lines is formed to become larger as it goes upward. The lower end of the upper fold line is connected to the engagement slit. The upper ends of the lower folded lines are connected to the engagement slits on both sides of the lower end of the upper folded line.

When assembling the tray of the present invention, when the inner flap is folded inward relative to the side wall, the upper portion of the inner flap is folded relative to the upper portion of the side wall at a single upper fold line, and the lower portion of the inner flap is folded relative to the lower portion of the side wall at two lower fold lines.
When the inner flap is bent relative to the side wall, the lower portion of the side wall is pushed outward and the upper portion of the side wall is pulled inward. This causes the engagement slit to be open in the left-right direction, making it easier to insert the lower portion of the engagement piece into the engagement slit.

In a further embodiment of the present invention, an auxiliary bending line may be formed from the upper edge of the side wall to the engagement slit.
In this way, when the inner flap is folded against the side wall, the area of the upper part of the side wall that is closer to the inner flap than the auxiliary fold line is more likely to be pulled inward, causing the engagement slit to open widely.

In a reference example of the present invention, the side wall below the engagement slit may be thinned by being pressed in the thickness direction to increase the opening width of the engagement slit.

In the present invention, a notch extending upward is formed at the end of the engagement slit on the side wall side, and a protrusion is formed on the engagement piece to engage with the upper edge of the engagement slit from below. Also, the notch may be folded back in an arc shape toward the end wall side.

In this configuration, the protruding portion of the engagement piece engages with the upper edge of the engagement slit, thereby preventing the engagement piece from slipping out of the engagement slit. When removing the engagement piece from the engagement slit, the upper edge of the engagement slit is pushed inward to separate the upper edge of the engagement slit from the protruding portion of the engagement piece.
In the above-mentioned configuration, since an upward notch is formed at the other end of the engagement slit, when the upper edge of the engagement slit is pushed inward, the upper edge of the engagement slit can be pushed in largely, which makes it easy to remove the engagement piece from the engagement slit.

In a reference example of the present invention, the engaging piece may be formed with a recessed portion recessed toward the top, and the side wall below the engaging slit may be inserted into the recessed portion. In this case , it is possible to prevent the engaging piece from shifting relative to the side wall, and to stabilize the crosspiece.

In one embodiment of the present invention, an inclined plate may be provided extending downward from the leading edge of the crosspiece, in which case the inclined plate is inclined away from the inner surface of the end wall as it moves from the upper edge to the lower edge, and the lower edge of the inclined plate is configured to contact the upper surface of the base plate.

In this case, the contents can be stably stored in the tray by forming auxiliary inclined fold lines extending in the left-right direction on the inclined plate so that the inclined plate bends along the shape of the contents that are in contact with the upper surface of the inclined plate.

In the blank sheet and tray of the present invention, the engagement slit opens automatically when the inner flap is folded against the side wall, making it easier to insert the engagement piece into the engagement slit. Therefore, the blank sheet and tray of the present invention can improve the work efficiency during assembly.

FIG. 2 is a perspective view of the tray according to the first embodiment of the present invention, as viewed from the upper front left. 3A and 3B are diagrams showing blank sheets for a tray according to the first embodiment of the present invention; 1 is a perspective view of the end wall of a tray according to a first embodiment of the present invention before assembly, viewed from the upper left front side. FIG. 3 is a perspective view showing a state in which an inner flap is folded against a side wall in the tray according to the first embodiment of the present invention. FIG. 4 is a perspective view showing a state in which an engagement piece is inserted into an engagement slit in the tray according to the first embodiment of the present invention. FIG. FIG. 11 is a perspective view of a tray according to a second embodiment of the present invention, as viewed from the upper front left. 13A and 13B are diagrams showing a blank sheet for a tray according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the accompanying drawings.
In the description of each embodiment, the same components are denoted by the same reference numerals, and duplicate descriptions will be omitted.
In the following description, the front, rear, left and right directions are set for the sake of convenience in describing the tray of this embodiment, and do not limit the configuration or usage state of the tray.

[First embodiment]
1, the tray 1A of the first embodiment includes a bottom plate 10, front and rear end walls 20, 20 and left and right side walls 30, 30 connected to the bottom plate 10, and an inner flap 40 connected to the front and rear edges of the side wall 30. The tray 1A also includes front and rear crosspieces 50, 50 connected to the upper edges of both end walls 20, 20, and engagement pieces 60 connected to the left and right edges of the crosspiece 50.

The tray 1A is formed by mountain-folding or valley-folding a blank sheet S1 cut out from a cardboard sheet at each fold line, as shown in Fig. 2. The blank sheet S1 shown in Fig. 2 is arranged so that the inner side is visible.
The fold lines of the blank sheet S1 are lines (pressed creases) formed by linearly pressing the surface of the blank sheet S1. Note that the creases may be formed with intermittent cuts. In this way, it becomes easier to fold the blank sheet S1 at the creases.
Alternatively, the folded lines may be formed by forming intermittent linear cuts, such as half-cut cuts that cut only the surface of the sheet, or cuts that penetrate the sheet.

As shown in FIG. 3, the bottom plate 10 is formed in a rectangular shape. Front and rear end walls 20, 20 are connected to the front and rear edges of the bottom plate 10, and left and right side walls 30, 30 are connected to the left and right edges of the bottom plate 10.

As shown in FIG. 1, the front end wall 20 is connected to the front edge of the bottom plate 10 via a fold line and extends upward from the front edge of the bottom plate 10. The rear end wall 20 is connected to the rear edge of the bottom plate 10 via a fold line and extends upward from the rear edge of the bottom plate 10. The front and rear end walls 20, 20 are formed in the same rectangular shape. The front and rear end walls 20, 20 are formed perpendicular to the bottom plate 10.

At the corner between the bottom plate 10 and the end wall 20, a connecting hole 11 penetrates in the center in the left-right direction. In addition, at the upper edge of the end wall 20, a connecting part 12 protrudes upward in the center in the left-right direction.

A front crosspiece 50 is connected to the upper edge of the front end wall 20 via a fold line. The front crosspiece 50 is formed in a rectangular shape along the upper edge of the front end wall 20. The front crosspiece 50 is formed perpendicular to the front end wall 20. The middle part in the left-right direction of the tip edge (rear edge) of the front crosspiece 50 is recessed toward the front.

A left front engagement piece 60 is connected to the left edge of the front crosspiece 50 via a folding line (see FIG. 3). The left front engagement piece 60 extends downward from the left edge of the crosspiece 50. The left front engagement piece 60 is formed perpendicular to the crosspiece 50.
An upper portion of the left front engagement piece 60 is overlapped with the outer surface of the left side wall 30. A lower portion of the left front engagement piece 60 is inserted into an engagement slit 70, which will be described later.

5, a protrusion 61 that protrudes rearward is formed at the lower rear edge of the left front engagement piece 60. The upper edge of the protrusion 61 is parallel to the upper edge of the engagement piece 60.
A recess 62 is formed in the lower part of the front edge of the left front engagement piece 60 and extends obliquely upward toward the rear (see FIG. 2).

As shown in FIG. 1, a right front engagement piece 60 is connected to the right edge of the front crosspiece 50 via a fold line (see FIG. 3). The right front engagement piece 60 is formed symmetrically with the left front engagement piece 60.

A rear crosspiece 50 is connected to the upper edge of the rear end wall 20. The rear crosspiece 50 is formed symmetrically with the front crosspiece 50 in the front-rear direction.
Left and right engagement pieces 60, 60 are connected to the left and right edges of the rear crosspiece 50 (see FIG. 3). The two rear engagement pieces 60, 60 are formed symmetrically with the two front engagement pieces 60, 60.

The left side wall 30 is connected to the left edge of the bottom plate 10 via a fold line and extends upward from the left edge of the bottom plate 10. The left side wall 30 is formed in a substantially rectangular shape. The left side wall 30 is formed perpendicular to the bottom plate 10.

As shown in FIG. 4, a front left inner flap 40 is connected to the front edge of the left side wall 30. The inner flap 40 is formed in a rectangular shape. The front left inner flap 40 extends rightward from the front edge of the left side wall 30. The inner flap 40 is formed perpendicular to the side wall 30.

The upper portion of the side wall 30 and the upper portion of the inner flap 40 are connected via an upper fold line L1. The upper fold line L1 is a ruled line formed on the back surface of the blank sheet S1 (see FIG. 2).
The upper fold line L1 is a boundary line between the upper portion of the side wall 30 and the upper portion of the inner flap 40. The upper fold line L1 is formed perpendicular to the upper edges of the side wall 30 and the inner flap 40 (see FIG. 2).

The lower part of the side wall 30 and the lower part of the inner flap 40 are connected via two lower fold lines L2, L2. The lower fold line L2 is a ruled line formed on the back surface of the blank sheet S1 (see FIG. 2). The two lower fold lines L2, L2 form the boundary between the lower part of the side wall 30 and the lower part of the inner flap 40.

The lower ends of both lower folded lines L2, L2 are connected to the apexes of the corners of the bottom plate 10. In this manner, the lower ends of both lower folded lines L2, L2 are connected.
The upper ends of the lower folded lines L2, L2 are spaced apart in the horizontal direction and are disposed on either side of the lower end of the upper folded line L1.
The horizontal distance between the lower broken lines L2, L2 is increased from the lower end to the upper end (see FIG. 2). In other words, the lower broken lines L2, L2 are arranged in a V-shape, and a triangular region R1 is formed between the lower broken lines L2, L2.

The lower fold line L2 on the side wall 30 side is inclined toward the side wall 30 with respect to the normal to the upper surface of the bottom plate 10. The inclination angle of the lower fold line L2 on the side wall 30 side is not limited, but it is preferable that the inclination angle be between 60 degrees and 85 degrees with respect to the normal to the upper surface of the bottom plate 10.
The lower fold line L2 on the inner flap 40 side is inclined toward the inner flap 40 with respect to the normal to the upper surface of the bottom plate 10. The inclination angle of the lower fold line L2 on the inner flap 40 side is not limited, but it is preferable that the inclination angle be between 60 degrees and 85 degrees with respect to the normal to the upper surface of the bottom plate 10.
Furthermore, the inclination angle of the lower fold line L2 on the side wall 30 side and the inclination angle of the lower fold line L2 on the inner flap 40 side may be different angles, but it is preferable that they are the same angle.

A left front engagement slit 70 is formed in the left side wall 30 and the left front inner flap 40 (see FIG. 2). The left front engagement slit 70 extends laterally from the front part of the left side wall 30 to the left edge part of the left front inner flap 40. The engagement slit 70 is a linear cut penetrating the side wall 30 and the inner flap 40.
In the state of the blank sheet S1 (see FIG. 2), the upper edge and the lower edge of the engagement slit 70 are in contact with each other, and the engagement slit 70 is closed.

The engagement slit 70 is located at the midpoint of the height of the side wall 30 and the inner flap 40. The lower end of the upper fold line L1 is connected to the front of the engagement slit 70. The upper ends of both lower fold lines L2, L2 are connected to the front of the engagement slit 70 on both sides of the lower end of the upper fold line L1.

The portion of the engagement slit 70 on the side wall 30 side is disposed so that the rear portion is lower than the front portion, and an inclined portion is formed between the front and rear portions (see FIG. 2).
An end 71 of the engagement slit 70 on the side wall 30 side is disposed forward of the center in the front-to-rear direction of the side wall 30. A notch 72 extending upward is formed in the end 71 of the engagement slit 70 on the side wall 30 side. This notch 72 is folded back forward into a semicircular shape.

The left side wall 30 has a bend auxiliary fold line L3 formed from the upper edge to the rear of the engagement slit 70. The bend auxiliary fold line L3 is a line formed on the back surface of the blank sheet S1 (see FIG. 2). The bend auxiliary fold line L3 is formed perpendicular to the upper edge of the side wall 30.

At the rear of the side wall 30 side of the engagement slit 70, the side wall 30 is crushed in the thickness direction below the engagement slit 70 to become thinner.

5, the lower part of the left front engagement piece 60 is inserted from the outside into the left front engagement slit 70. As a result, the upper part of the engagement piece 60 overlaps with the outer surface of the side wall 30, and the lower part overlaps with the inner surface of the side wall 30.
The upper edge of the protrusion 61 of the engagement piece 60 engages with the upper edge of the engagement slit 70 from below. In other words, the upper edge of the protrusion 61 engages with the edge of the side wall 30 above the engagement slit 70 from below.
The edge of the side wall 30 below the engagement slit 70 is inserted into the recess 62 of the engagement piece 60 .

3, a left rear inner flap 40 is connected to the rear edge of the left side wall 30. The left rear inner flap 40 is formed symmetrically with the left front inner flap 40 in the front-rear direction.
2, the upper portion of the left side wall 30 and the upper portion of the left rear inner flap 40 are connected via one upper fold line L1. Also, the lower portion of the left side wall 30 and the lower portion of the left rear inner flap 40 are connected via two lower fold lines L2, L2.

As shown in FIG. 3, a rear left engagement slit 70 is formed in the left side wall 30 and the rear left inner flap 40. The rear left engagement slit 70 is formed symmetrically in the front-to-rear direction with the front left engagement slit 70.

The right side wall 30 is formed symmetrically with the left side wall 30. In addition, the right side wall 30 is connected to front and rear inner flaps 40, 40, just like the left side wall 30. Furthermore, front and rear engagement slits 70, 70 are formed in the right side wall 30 and the front and rear inner flaps 40, 40.

As shown in FIG. 1, left and right engagement pieces 60, 60 connected to the front crosspiece 50 are inserted into the left and right engagement slits 70, 70 on the front side. Also, left and right engagement pieces 60, 60 connected to the rear crosspiece 50 are inserted into the left and right engagement slits 70, 70 on the rear side.

When assembling the tray 1A of the first embodiment, an operator first stands the left and right side walls 30, 30 against the bottom plate 10, and then folds the front and rear inner flaps 40, 40 inwardly against the side walls 30, as shown in FIG.
At this time, as shown in Fig. 4, the upper part of the inner flap 40 is bent relative to the upper part of the side wall 30 at one upper fold line L1. Also, the lower part of the inner flap 40 is bent relative to the lower part of the side wall 30 at two lower fold lines L2, L2. As a result, a triangular region R1 whose width increases from the lower end toward the upper part is formed between the lower part of the inner flap 40 and the lower part of the side wall 30.

By forming such region R1 between the lower part of the inner flap 40 and the lower part of the side wall 30, the lower part of the side wall 30 is pushed outward. Also, the upper part of the side wall 30 is pulled inward. Then, the upper part of the side wall 30 is bent at the bending auxiliary fold line L3, and the region R2 on the inner flap 40 side of the bending auxiliary fold line L3 is inclined inward.
In this manner, the lower edge of the engagement slit 70 is pushed outward and the upper edge of the engagement slit 70 is pulled inward, so that the engagement slit 70 is opened in the left-right direction.

Next, as shown in FIG. 1 , the worker raises the front and rear end walls 20 , 20 against the bottom plate 10 , overlaps the end walls 20 on the outer faces of the inner flaps 40 , and bends the engaging pieces 60 against the crosspieces 50 .
Furthermore, as shown in FIG. 5 , the worker bends the crosspiece 50 inward relative to the end wall 20 and inserts the lower portion of the engagement piece 60 into the engagement slit 70 from the outside of the side wall 30 .

When the engagement piece 60 is inserted into the engagement slit 70, the upper edge of the protrusion 61 of the engagement piece 60 engages from below with the upper edge of the engagement slit 70. Also, the lower side wall 30 of the engagement slit 70 is inserted into the recess 62 of the engagement piece 60.
1, the front and rear, left and right engagement pieces 60 are inserted into the front, rear, left and right engagement slits 70, respectively, thereby fixing the front and rear crosspieces 50, 50 to the left and right side walls 30, 30. This completes the assembly work of the tray 1A having the front and rear crosspieces 50, 50.

When two trays 1A are stacked one on top of the other, the front and rear connecting parts 12, 12 of the lower tray 1A are inserted into the front and rear connecting holes 11, 11 of the upper tray 1A, respectively, allowing the two trays 1A to be stacked stably.

When opening the crosspiece 50 after assembling the tray 1A, the worker pushes inward the upper edge of the engagement slit 70 on the side wall 30 side as shown in FIG. 5. This causes the upper edge of the engagement slit 70 to move inward relative to the protruding portion 61 of the engagement piece 60, and the engagement between the protruding portion 61 of the engagement piece 60 and the upper edge of the engagement slit 70 is released. This allows the lower portion of the engagement piece 60 to be pulled out of the engagement slit 70, and the crosspiece 50 can be opened.

In the tray 1A described above, when the inner flap 40 is folded against the side wall 30 during assembly, as shown in Figure 4, the lower part of the side wall 30 is pushed outward and the upper part of the side wall 30 is pulled inward, thereby opening the engagement slit 70.
In addition, in the tray 1A of the first embodiment, when the inner flap 40 is folded relative to the side wall 30, the upper portion of the side wall 30 is easily pulled inward by the auxiliary bending fold line L3, causing the engagement slit 70 to be in a wide open state.
In addition, in the tray 1A of the first embodiment, since the side wall 30 below the engagement slit 70 is thin, the opening width of the engagement slit 70 is large.

In this way, in the tray 1A of the first embodiment, by folding the inner flap 40 against the side wall 30, the engagement slit 70 automatically opens, making it easier to insert the engagement piece 60 into the engagement slit 70, as shown in FIG. 5. Therefore, the tray 1A of the first embodiment can improve the work efficiency during assembly.

In the tray 1A of the first embodiment, the protrusion 61 of the engagement piece 60 engages with the upper edge of the engagement slit 70, so that the engagement piece 60 can be reliably engaged with the engagement slit 70.
In the first embodiment of the tray 1A, the lower side wall 30 of the engagement slit 70 is inserted into the recess 62 of the engagement piece 60, thereby preventing the engagement piece 60 from shifting relative to the side wall 30 and stabilizing the crosspiece 50.

In the first embodiment of the tray 1A, a notch 72 is formed in the end 71 of the engagement slit 70 on the side wall 30 side, and the upper edge of the engagement slit 70 can be pushed inward significantly, so that the engagement piece 60 can be easily removed from the engagement slit 70.

Although the first embodiment of the present invention has been described above, the present invention is not limited to the first embodiment, and can be appropriately modified without departing from the spirit of the present invention.
In the tray 1A of the first embodiment, as shown in Fig. 1, the front and rear battens 50, 50 are provided, but the battens 50 may be provided only on either the front or the rear. Furthermore, the shapes of the engagement pieces 60 and the engagement slits 70 are not limited, and the engagement pieces 60 and the engagement slits 70 may be provided only on either the left or right side.

The angle of inclination of the lower fold line L2 relative to the perpendicular line to the top surface of the bottom plate 10 is not limited. By increasing the angle of inclination of the lower fold line L2 on the inner flap 40 side, the amount by which the lower portion of the side wall 30 is pushed out when the inner flap 40 is folded relative to the side wall 30 can be increased, and the opening width of the engagement slit 70 can be increased.

The tray 1A in the first embodiment is made of cardboard, but the tray may also be made of any known paperboard.

[Second embodiment]
As shown in FIG. 6, the tray 1B of the second embodiment differs from the tray 1A of the first embodiment (see FIG. 1) in that it includes an inclined plate 90. As shown in FIG.
The tray 1B of the second embodiment is formed by mountain-folding or valley-folding the blank sheet S2 shown in Fig. 7 at each fold line. The blank sheet S2 shown in Fig. 7 is arranged so that the inner side is visible.

As shown in FIG. 6, the tray 1B of the second embodiment is provided with an inclined plate 90 that extends downward from the tip edge (front edge) of the rear crosspiece 50.
The upper edge of the inclined plate 90 is connected via a folded line to the center in the left-right direction of the tip edge of the rear crosspiece 50. The inclined plate 90 is formed in a trapezoidal shape such that the width in the left-right direction increases from the upper edge to the lower edge.
The inclined plate 90 is inclined from the upper edge to the lower edge so as to move away from the inner surface of the rear end wall 20. The lower edge of the inclined plate 90 is in contact with the upper surface of the bottom plate 10. In addition, the left and right ends of the lower end of the inclined plate 90 are in contact with the inner surfaces of both side walls 30, 30.

The inclined plate 90 is a plate for supporting the rearmost contents when multiple contents are stored in the tray 1B in a state inclined with respect to the bottom plate 10. Therefore, the side of the contents comes into contact with the upper surface of the inclined plate 90.
Upper and lower auxiliary inclination lines L4, L4 extending in the left-right direction are formed on the inclined plate 90. The auxiliary inclination lines L4 are lines formed on the upper surface of the inclined plate 90, and are constituted by a ruled line or a plurality of notches.

In the second embodiment of the tray 1B, the inclined plate 90 bends appropriately at the upper and lower auxiliary inclination fold lines L4, L4 to fit the shape of the contents that are in contact with the upper surface of the inclined plate 90, so that the contents can be stably stored in the tray 1B.

The above describes the second embodiment of the present invention. However, the present invention is not limited to the second embodiment, and similarly to the first embodiment, it can be modified appropriately without departing from the spirit of the present invention.
For example, an inclined plate may be provided extending downward from the leading edge (rear edge) of the front crosspiece 50 .

1A Tray (First embodiment)
1B Tray (Second embodiment)
REFERENCE SIGNS LIST 10 Bottom plate 11 Connection hole 12 Connection portion 20 End wall 30 Side wall 40 Inner flap 50 Crosspiece 60 Engagement piece 61 Protrusion 62 Recess 70 Engagement slit 71 End 90 Inclined plate L1 Upper fold line L2 Lower fold line L3 Bend auxiliary fold line L4 Incline auxiliary fold line S1 Blank sheet (first embodiment)
S2 Blank sheet (second embodiment)

Claims (3)

The bottom plate and
front and rear end walls and left and right side walls connected to the bottom plate;
An inner flap is connected to the front-rear edge of the side wall and overlaps the inner surface of the end wall;
A crosspiece connected to an upper edge portion of the end wall;
and an engagement piece provided adjacent to the left and right edges of the crosspiece,
An engagement slit is formed extending laterally from the side wall to the inner flap,
A lower portion of the engagement piece is inserted into the engagement slit from the outside,
The upper portion of the side wall and the upper portion of the inner flap are connected via an upper fold line,
The lower portion of the side wall and the lower portion of the inner flap are connected via two lower fold lines,
The horizontal distance between the lower folded lines is increased toward the top,
The lower end of the upper folded line is connected to the engagement slit,
The upper ends of the lower folded lines are connected to the engagement slits on both sides of the lower end of the upper folded line,
An upwardly extending notch is formed at an end of the engagement slit on the side wall side,
A blank sheet for forming a tray, the engagement piece having a protrusion formed thereon that engages with the upper edge of the engagement slit from below. 2. The blank sheet according to claim 1,
A blank sheet, wherein the slit is folded back in an arc shape toward the end wall side. The bottom plate and
front and rear end walls and left and right side walls connected to the bottom plate;
An inner flap is connected to the front-rear edge of the side wall and overlaps the inner surface of the end wall;
A crosspiece connected to an upper edge portion of the end wall;
and an engagement piece provided adjacent to the left and right edges of the crosspiece,
An engagement slit is formed extending laterally from the side wall to the inner flap,
A lower portion of the engagement piece is inserted into the engagement slit from the outside,
The upper portion of the side wall and the upper portion of the inner flap are connected via an upper fold line,
The lower portion of the side wall and the lower portion of the inner flap are connected via two lower fold lines,
The horizontal distance between the lower folded lines is increased toward the top,
The lower end of the upper folded line is connected to the engagement slit,
The upper ends of the lower folded lines are connected to the engagement slits on both sides of the lower end of the upper folded line,
An upwardly extending notch is formed at an end of the engagement slit on the side wall side,
A tray characterized in that the engagement piece is formed with a protrusion that engages with an upper edge of the engagement slit from below.