CN210793997U - Foldable tray box - Google Patents

Abstract

The utility model discloses a foldable tray box, which comprises a foldable box body consisting of a first folding plate and a second folding plate, and a box cover; the first folding plate comprises a lower bottom plate and first folding side plates symmetrically connected to two sides of the lower bottom plate through first crease lines; the second folding plate comprises an upper bottom plate and second folding side plates which are symmetrically connected to the two sides of the upper bottom plate through second crease lines; the first folding plate and the second folding plate are vertically distributed in a crossed manner, and the upper base plate is attached to the lower base plate; the first folding side plate is upwards folded to be vertically distributed with the lower bottom plate through a first crease line; the second folding side plate is upwards folded to the upper bottom plate through a second folding mark to be vertically distributed; the adjacent side edges of the first folding side plate and the second folding side plate are connected and fixed in a matching way to form four side plates of the foldable box body; the box of this product accessible fourth crease line, slope crease line and third crease line combined action realize folding reduction height to occupation space when effectively saving the product and not using.

Description

Foldable tray box

Technical Field

The utility model belongs to the technical field of the tray case, especially, relate to a folding tray case.

Background

Pallets (pallets), also known as pallets and plywood, are known from the national standard "logistic terms" of china and refer to horizontal platform arrangements for containerization, stacking, handling and transport of goods and products placed as unit loads. As a kind of container equipment similar to a container, the pallet is widely used in the fields of production, transportation, storage and circulation, and is considered as one of two key innovations in the logistics industry of the 20 th century. The tray is as the important loading and unloading of commodity circulation operation in-process, stores and the transportation equipment, and supporting the use with fork truck plays huge effect in modern commodity circulation, and its benefit that brings for modern commodity circulation mainly reflects: the unitization, standardization and standardization of the article package can be realized, the articles are protected, and the logistics and the commodity flow are facilitated. The trays in logistics are distinguished according to materials, purposes, table tops, forking modes and structures of forklifts, and are of various types.

The tray box is a box body placed on the tray, so the volume of the tray box is generally not small; the common tray box is fixed, occupies a large space when not in use, and is very troublesome to store.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved

The to-be-solved technical problem of the utility model is to provide an accessible is folding to be subtracted province and accomodate storage space's tray case.

(II) technical scheme

In order to solve the technical problem, the utility model provides a foldable tray box, which comprises a foldable box body and a box cover; the foldable box body comprises a first folding plate and a second folding plate; the first folding plate comprises a lower bottom plate positioned in the middle and first folding side plates symmetrically and integrally connected to two sides of the lower bottom plate; a first crease line is arranged between the lower bottom plate and the first folding side plate; the second folding plate comprises an upper bottom plate positioned in the middle and second folding side plates symmetrically and integrally connected to two sides of the upper bottom plate; a second crease line is arranged between the upper bottom plate and the second folding side plate;

the second folding plate is vertically and crossly distributed on the first folding plate, an upper bottom plate of the second folding plate is matched with and covers a lower bottom plate of the first folding plate, and the upper bottom plate is connected with the lower bottom plate in a fitting manner; the first folding side plate is upwards folded to be vertically distributed with the lower bottom plate through a first crease line; the second folding side plate is upwards folded to the upper bottom plate through a second crease line to be vertically distributed; the two first folding side plates and the adjacent side edges of the two second folding side plates are fixedly connected in a matching mode to form four side plates of the foldable box body;

the two first folding side plates are provided with third crease lines which are symmetrically distributed and parallel to the first crease lines, each first folding side plate is also provided with two inclined crease lines which are symmetrically distributed and extend to the top by taking two end points of the third crease line as starting points, and the included angle between each inclined crease line and the corresponding third crease line is 45 degrees; and the two second folding side plates are provided with fourth crease lines which are symmetrically distributed and are parallel to the second crease lines, and the heights of the fourth crease lines and the third crease lines are the same.

Wherein, both sides of the first folding side plate are also provided with fixed side plates which are integrally connected and symmetrically distributed, and the joint between the fixed side plates and the first folding side plate is provided with a fifth crease line; the fixed side plate is bent through the fifth crease line and is matched with the second folded side plate to be attached and fixed.

Wherein, the upper bottom plate and the lower bottom plate are welded and fixed after being covered and jointed; the joint of the fixed side plate and the second folding side plate is also fixed by welding.

The foldable tray box also comprises foldable supporting plates, each foldable supporting plate comprises a first supporting plate and a second supporting plate, and the number of the first supporting plate and the number of the second supporting plates are two; the first supporting plate comprises a first supporting side plate and a second supporting side plate which are integrally connected, and a sixth crease line is arranged at the joint between the first supporting side plate and the second supporting side plate; the second supporting plate comprises a third supporting side plate and a fourth supporting side plate which are integrally connected, and a seventh crease line is arranged at the connecting position between the third supporting side plate and the fourth supporting side plate;

the first supporting plate enables the first supporting side plate and the second supporting side plate to be vertically distributed through bending at the sixth crease line, and the second supporting plate enables the third supporting side plate and the fourth supporting side plate to be also vertically distributed through bending at the seventh crease line; the side edge of the first supporting side plate of one first supporting plate is matched and connected with and fixed to the side edge of the third supporting side plate of one second supporting plate, the side edge of the fourth supporting side plate of one second supporting plate is matched and connected and fixed to the sixth crease line of the second supporting side plate of the other first supporting plate, the side edge of the first supporting side plate of the other first supporting plate is matched and connected and fixed to the side edge of the third supporting side plate of the other second supporting plate, and the side edge of the fourth supporting side plate of the other second supporting plate is matched and connected and fixed to the sixth crease line of the second supporting side plate of the one first supporting plate; the two first supporting plates and the two second supporting plates are fixedly connected in sequence to form a foldable supporting plate with four sides tightly attached to the inner side wall of the foldable box body.

And an eighth crease line parallel to the seventh crease line is arranged in the middle of the fourth supporting side plate.

And the two second folding side plates of the second folding plate are symmetrically provided with carrying holes.

The box cover comprises a top plate matched with the top opening of the foldable box body, and a left side plate, a right side plate, an upper side plate and a lower side plate which are integrally connected to the periphery of the top plate; the left side plate, the right side plate, the upper side plate and the lower side plate are respectively provided with a left crease line, a right crease line, an upper crease line and a lower crease line at the connection part with the top plate;

the left side plate, the right side plate, the upper side plate and the lower side plate are respectively bent downwards to be vertically distributed with the top plate through a left crease line, a right crease line, an upper crease line and a lower crease line; the side edges of the left side plate, the right side plate, the upper side plate and the lower side plate are respectively connected and fixed in sequence in a matching way.

Wherein, the two sides of the upper side plate and the lower side plate are both provided with extension plates which are integrally connected with each other, and the joints among the extension plates, the upper side plate and the lower side plate are provided with ninth crease lines;

when the left side plate, the right side plate, the upper side plate and the lower side plate are respectively bent downwards to be vertically distributed with the top plate through the left crease line, the right crease line, the upper crease line and the lower crease line, the extension plate is also bent to be respectively matched, attached and fixed with the left side plate and the right side plate through the ninth crease line.

(III) advantageous effects

Compared with the prior art, the height of the box body of the tray box can be reduced by folding the box body, so that the occupied space of the tray box when not in use is effectively reduced, and the tray box is convenient to store; wherein, the setting of collapsible backup pad not only can be used for the supporting box, prevents that the box from because of crease line is automatic folding, can increase the whole thickness of box moreover, guarantees the firmness of tray case when using.

Drawings

Fig. 1 is a schematic structural view of the foldable tray box of the present invention.

Fig. 2 is a schematic structural view of the first folding plate in the unfolded state of the present invention.

Fig. 3 is a schematic structural view of the second folding plate in the unfolded state of the present invention.

Fig. 4 is a schematic structural diagram of the foldable box of the present invention.

Fig. 5 is a schematic structural view of the first folding of the foldable box of the present invention.

Fig. 6 is a schematic view of the folding structure of the foldable box of the present invention.

Fig. 7 is a distribution diagram of the solder joints on the fixing side plate of the present invention.

Fig. 8 is a schematic structural diagram of the first support plate of the present invention.

Fig. 9 is a schematic structural view of the second support plate of the present invention.

Fig. 10 is a schematic structural view of the foldable support plate of the present invention.

Fig. 11 is a schematic structural view of the foldable support plate in the folded state of the present invention.

Fig. 12 is a development state diagram of the cover of the present invention.

Description of reference numerals: 1. a foldable box body; 2. a box cover; 3. a foldable support plate; 11. a first folding plate; 12. a second folding plate; 21. a top plate; 22. a left side plate; 23. a right side plate; 24. an upper edge plate; 25. a lower edge plate; 26. an extension plate; 27. cutting; 31. a first support plate; 32. a second support plate; 111. a lower base plate; 112. a first folded side panel; 113. a first crease line; 114. fixing the side plate; 115. a fifth crease line; 121. an upper base plate; 122. a second folded side panel; 123. a second crease line; 221. a left crease line; 231. a right crease line; 241. an upper crease line; 251. a lower crease line; 261. a ninth crease line; 311. a first support side plate; 312. a second support side plate; 313. a sixth crease line; 321. a third support side plate; 322. a fourth supporting side plate; 323. a seventh crease line; 1121. a third crease line; 1122. an inclined crease line; 1221. a fourth crease line; 1222. a carrying hole; 3221. an eighth crease line.

Detailed Description

The following detailed description of the embodiments of the present invention is provided with reference to the accompanying drawings and examples. The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.

The structure of the foldable tray box of the utility model is shown in figure 1, figure 2, figure 3 and figure 4, and the foldable tray box comprises a foldable box body 1 and a box cover 2; the foldable box body 1 comprises a first folding plate 11 and a second folding plate 12; the first folding plate 11 includes a lower plate 111 in the middle, and first folding side plates 112 symmetrically and integrally connected to both sides of the lower plate 111; a first crease line 113 is arranged between the lower bottom plate 111 and the first folding side plate 112; the second folding plate 12 includes an upper bottom plate 121 in the middle, and second folding side plates 122 symmetrically and integrally connected to both sides of the upper bottom plate 121; a second crease line 123 is arranged between the upper bottom plate 121 and the second folded side plate 122;

the second folding plates 12 are vertically and crosswise distributed on the first folding plates 11, the upper bottom plates 121 of the second folding plates 12 are matched with and cover the lower bottom plates 111 of the first folding plates 11, and the upper bottom plates 121 are attached and connected with the lower bottom plates 111; the first folding side panel 112 is folded upwards to be vertically distributed with the lower bottom panel 111 through a first crease line 113; the second folded side panel 122 is folded upward to the upper bottom panel 121 by the second crease line 123 to be vertically distributed; the two first folding side plates 112 and the adjacent side edges of the two second folding side plates 122 are connected and fixed in a matching manner to form four side plates of the foldable box body 1; the box cover 2 can cover the foldable box body 1 in the state to form a closed storage space;

the two first folding side panels 112 are respectively provided with third folding lines 1121 which are symmetrically distributed and parallel to the first folding line 113, each first folding side panel 112 is further provided with two inclined folding lines 1122 which are symmetrically distributed and extend to the top with two end points of the third folding line 1121 as starting points, and an included angle between each inclined folding line 1122 and the corresponding third folding line 1121 is 45 degrees; the two second folded side panels 122 are respectively provided with a fourth crease line 1221 which is symmetrically distributed and parallel to the second crease line 123, and the heights of the fourth crease line 1221 and the third crease line 1121 are the same. As shown in fig. 5 and 6, the second folded side panel 122 is folded toward the inside of the foldable box 1 via the fourth crease line 1221, in the process, the first folded side panel 112 is synchronously folded toward the outside of the foldable box 1 via the third crease line 1121, and simultaneously the inclined crease line 1122 of the first folded side panel 112 is synchronously folded; after the second folded side panel 122 is folded and flattened along with the second crease line 1221, the two first folded side panels 112 are folded and flattened toward the inside of the foldable box body 1 through the third crease line 1121; this is the folded state of the foldable box 1; then, the case cover 2 can be covered on the foldable case body 1 in a folded state for storage, thereby effectively reducing the storage space when the product is not used. In addition, the length of the first crease line 113 is greater than or equal to twice the distance from the fourth crease line 1221 to the top of the second folded side panel 122; the distance between the third folding line 1121 and the top of the first folding side panel 112 is less than or equal to the length of the second folding line 123.

As shown in fig. 2, 4, 5, 6 and 7, in the present embodiment, two sides of the first folding side plate 112 are further provided with a fixed side plate 114 integrally connected and symmetrically distributed, and a fifth crease line 115 is provided at a connection between the fixed side plate 114 and the first folding side plate 112; the fixed side panel 114 is bent by the fifth crease line 115 to be matched and attached to and fixed with the second folded side panel 122. Wherein, both ends of the third folding line 1121 extend into the fixing edge plate 114.

In this embodiment, the upper plate 121 and the lower plate 111 are welded and fixed after being covered and attached; the fixing side plate 114 is also fixed to the second folded side plate 122 by welding. The periphery of the covering surface between the upper base plate 121 and the lower base plate 111 is fixedly connected through welding points which are uniformly distributed at intervals, and each side is provided with at least nine welding points; each fixed side plate 114 also realizes the fixed connection with the second folded side plate 122 through welding points which are evenly distributed at intervals, as shown in fig. 7, each fixed side plate 114 has eight rows of welding points from top to bottom, and each row of welding points has two welding points.

As shown in fig. 8, 9 and 10, in the present embodiment, the foldable tray box further includes a foldable support plate 3, the foldable support plate 3 includes a first support plate 31 and a second support plate 32, and there are two first support plates 31 and two second support plates 32; the first support plate 31 comprises a first support side plate 311 and a second support side plate 312 which are integrally connected, and a sixth crease line 313 is arranged at the joint between the first support side plate 311 and the second support side plate 312; the second supporting plate 32 includes a third supporting side plate 321 and a fourth supporting side plate 322 integrally connected, and a seventh crease line 323 is disposed at a connection position between the third supporting side plate 321 and the fourth supporting side plate 322;

the first supporting plate 31 makes the first supporting side plate 311 and the second supporting side plate 312 vertically distributed through bending at the sixth crease line 313, and the second supporting plate 32 makes the third supporting side plate 321 and the fourth supporting side plate 322 vertically distributed through bending at the seventh crease line 323; the side edge of the first supporting side plate 311 of one of the first supporting plates 31 is fixedly connected with the side edge of the third supporting side plate 321 of one of the second supporting plates 32 in a matching manner, the side edge of the fourth supporting side plate 322 of one of the second supporting plates 32 is fixedly connected with the sixth crease line 313 of the second supporting side plate 312 of the other of the first supporting plates 31 in a matching manner, the side edge of the first supporting side plate 311 of the other of the first supporting plates 31 is fixedly connected with the side edge of the third supporting side plate 321 of the other of the second supporting plates 32 in a matching manner, and the side edge of the fourth supporting side plate 322 of the other of the second supporting plates 32 is fixedly connected with the sixth crease line 313 of the second supporting side plate 312 of one of the first supporting plates 31 in a matching manner; the four first support plates 31 and the four second support plates 32 are sequentially and fixedly connected to form a foldable support plate 3 with four sides closely attached to the inner side wall of the foldable box body 1. Wherein, the side edges of the first supporting side plate 311 and the third supporting side plate 321 are partially overlapped with each other and are fixedly connected through a row of welding points which are uniformly distributed at intervals; the side edge of the fourth supporting side panel 322 is also fixedly connected to the sixth crease line 313 of the second supporting side panel 312 by a change point.

As shown in fig. 9 and 10, in the present embodiment, an eighth crease line 3221 parallel to the seventh crease line 323 is disposed in the middle of the fourth supporting side panel 322. As shown in fig. 11, when the fourth supporting side panel 322 is folded toward the inside of the foldable supporting panel 3 by the eighth crease line 3221, the foldable supporting panel 3 can be folded to be flat at the bottom of the foldable box 1, and then the foldable box 1 is folded, and then the cover 2 is covered, so as to achieve the function of folding and storing the product. In addition, the distance between the first crease line 113 and the third crease line 1121 is matched with the thickness of the folded foldable support plate 3, so that the folded foldable support plate 3 can be conveniently placed into the folded foldable box body 1 after being folded.

As shown in fig. 3, 4 and 5, in this embodiment, two of the second folding side plates 122 of the second folding plate 12 are symmetrically provided with carrying holes 1222, so that a person can move the tray box by inserting a handle into the carrying holes 1222 as a force point.

As shown in fig. 1 and 12, in the present embodiment, the cover 2 includes a top plate 21 matching with the top opening of the foldable box 1, and a left side plate 22, a right side plate 23, an upper side plate 24 and a lower side plate 25 integrally connected to the four peripheries of the top plate 21; the left side plate 22, the right side plate 23, the upper side plate 24 and the lower side plate 25 are respectively provided with a left crease line 221, a right crease line 231, an upper crease line 241 and a lower crease line 251 at the connection parts with the top plate 21;

the left side plate 22, the right side plate 23, the upper side plate 24 and the lower side plate 25 are respectively bent downwards to be vertically distributed with the top plate 21 through a left crease line 221, a right crease line 231, an upper crease line 241 and a lower crease line 251; the left side plate 22, the right side plate 23, the upper side plate 24 and the lower side plate 25 are respectively connected and fixed in sequence. The heights of the left side plate 22, the right side plate 23, the upper side plate 24 and the lower side plate 25 after bending are matched with each other; the distance between the first folding line 113 and the third folding line 1121 is matched with the height of the four side panels after being folded.

As shown in fig. 12, in the present embodiment, both sides of the upper side plate 24 and the lower side plate 25 are provided with extension plates 26 integrally connected thereto, and the joints between the extension plates 26 and the upper side plate 24 and the lower side plate 25 are provided with ninth crease lines 261;

when the left, right, upper and lower panels 22, 23, 24 and 25 are respectively bent downward to be vertically distributed with the top panel 21 by the left, right, upper and lower crease lines 221, 231, 241 and 251, the extension panel 26 is also bent to be respectively matched and attached to and fixed with the left and right panels 22 and 23 by the ninth crease line 261. The matching and jointing parts of the extension plate 26 and the left and right side plates can also be fixedly connected through welding spots. In addition, the case cover 2 may be cut out from a rectangular plate; firstly, a left crease line 221, a right crease line 231, an upper crease line 241 and a lower crease line 251 are inwards arranged at equal intervals on four edges of the whole rectangular plate; next, the cuts 27 are provided at both ends of the upper crease line 241 and the lower crease line 251, the cuts 27 are cut along the crease lines at the intersection of the left crease line 221 and the right crease line 231, and the cuts 27 cut and separate both ends of the left crease line 221 and the right crease line 231 into the ninth crease line 261.

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the technical principle of the present invention, and these improvements and decorations should also be regarded as the protection scope of the present invention.

Claims (8)

1. A foldable tray box characterized in that: the foldable tray box comprises a foldable box body (1) and a box cover (2); the foldable box body (1) comprises a first folding plate (11) and a second folding plate (12); the first folding plate (11) comprises a lower bottom plate (111) positioned in the middle and first folding side plates (112) symmetrically and integrally connected to two sides of the lower bottom plate (111); a first crease line (113) is arranged between the lower bottom plate (111) and the first folding side plate (112); the second folding plate (12) comprises an upper bottom plate (121) positioned in the middle and second folding side plates (122) symmetrically and integrally connected to two sides of the upper bottom plate (121); a second crease line (123) is arranged between the upper bottom plate (121) and the second folding side plate (122);

the second folding plate (12) is vertically and crosswise distributed on the first folding plate (11), an upper bottom plate (121) of the second folding plate (12) is matched with and covers a lower bottom plate (111) of the first folding plate (11), and the upper bottom plate (121) is attached to and connected with the lower bottom plate (111); the first folding side plate (112) is folded upwards to be vertically distributed with the lower bottom plate (111) through a first crease line (113); the second folding side plate (122) is folded upwards to the upper bottom plate (121) through a second crease line (123) to be vertically distributed; the two first folding side plates (112) and the adjacent side edges of the two second folding side plates (122) are fixedly connected in a matching way to form four side plates of the foldable box body (1);

third crease lines (1121) which are symmetrically distributed and are parallel to the first crease lines (113) are arranged on the two first folding side plates (112), two inclined crease lines (1122) which are symmetrically distributed and extend to the top with two end points of the third crease lines (1121) as starting points are further arranged on each first folding side plate (112), and the included angle between each inclined crease line (1122) and the corresponding third crease line (1121) is 45 degrees; and the two second folding side plates (122) are respectively provided with a fourth crease line (1221) which is symmetrically distributed and is parallel to the second crease line (123), and the heights of the fourth crease line (1221) and the third crease line (1121) are the same.

2. The collapsible pallet box of claim 1, wherein: fixed side plates (114) which are integrally connected and symmetrically distributed are further arranged on two sides of the first folding side plate (112), and a fifth crease line (115) is arranged at the joint between the fixed side plates (114) and the first folding side plate (112); the fixed side plate (114) is bent through a fifth crease line (115) and is matched and attached with the second folding side plate (122) for fixation.

3. The collapsible pallet box of claim 2, wherein: the upper bottom plate (121) and the lower bottom plate (111) are welded and fixed after being covered and attached; the joint of the fixed side plate (114) and the second folding side plate (122) is also fixed by welding.

4. A collapsible pallet box according to any one of claims 1 to 3, characterised in that: the foldable tray box also comprises foldable supporting plates (3), wherein each foldable supporting plate (3) comprises a first supporting plate (31) and a second supporting plate (32), and the number of the first supporting plate (31) and the number of the second supporting plate (32) are two respectively; the first supporting plate (31) comprises a first supporting side plate (311) and a second supporting side plate (312) which are integrally connected, and a sixth crease line (313) is arranged at the joint between the first supporting side plate (311) and the second supporting side plate (312); the second supporting plate (32) comprises a third supporting side plate (321) and a fourth supporting side plate (322) which are integrally connected, and a seventh crease line (323) is arranged at the connecting position between the third supporting side plate (321) and the fourth supporting side plate (322);

the first supporting plate (31) enables the first supporting side plate (311) and the second supporting side plate (312) to form vertical distribution through bending at a sixth crease line (313), and the second supporting plate (32) enables the third supporting side plate (321) and the fourth supporting side plate (322) to also form vertical distribution through bending at a seventh crease line (323); the side edge of the first supporting side plate (311) of one first supporting plate (31) is matched, connected and fixed with the side edge of the third supporting side plate (321) of one second supporting plate (32), the side edge of the fourth supporting side plate (322) of one second supporting plate (32) is matched, connected and fixed at the sixth crease line (313) of the second supporting side plate (312) of the other first supporting plate (31), the side edge of the first supporting side plate (311) of the other first supporting plate (31) is matched, connected and fixed with the side edge of the third supporting side plate (321) of the other second supporting plate (32), and the side edge of the fourth supporting side plate (322) of the other second supporting plate (32) is matched, connected and fixed at the sixth crease line (313) of the second supporting side plate (312) of one first supporting plate (31); the two first supporting plates (31) and the two second supporting plates (32) are fixedly connected in sequence to form a foldable supporting plate (3) with four sides tightly attached to the inner side wall of the foldable box body (1).

5. The collapsible pallet box of claim 4, wherein: an eighth crease line (3221) parallel to the seventh crease line (323) is arranged in the middle of the fourth supporting side plate (322).

6. The collapsible pallet box of claim 1, wherein: two second folding side plates (122) of the second folding plate (12) are symmetrically provided with carrying holes (1222).

7. The collapsible pallet box of claim 1, wherein: the box cover (2) comprises a top plate (21) matched with the top opening of the foldable box body (1), and a left side plate (22), a right side plate (23), an upper side plate (24) and a lower side plate (25) which are integrally connected to the periphery of the top plate (21); the left side plate (22), the right side plate (23), the upper side plate (24) and the lower side plate (25) are respectively provided with a left crease line (221), a right crease line (231), an upper crease line (241) and a lower crease line (251) at the connection parts with the top plate (21);

the left side plate (22), the right side plate (23), the upper side plate (24) and the lower side plate (25) are respectively bent downwards to be vertically distributed with the top plate (21) through a left crease line (221), a right crease line (231), an upper crease line (241) and a lower crease line (251); the side edges of the left side plate (22), the right side plate (23), the upper side plate (24) and the lower side plate (25) are respectively connected and fixed in sequence in a matching way.

8. The collapsible pallet box of claim 7, wherein: extension plates (26) connected with the upper side plate (24) and the lower side plate (25) are arranged on two sides of the upper side plate (24) and the lower side plate (25) in an integrated mode, and a ninth crease line (261) is arranged at the connecting position of the extension plates (26) and the upper side plate (24) and the lower side plate (25);

when the left side plate (22), the right side plate (23), the upper side plate (24) and the lower side plate (25) are respectively bent downwards to be vertically distributed with the top plate (21) through the left crease line (221), the right crease line (231), the upper crease line (241) and the lower crease line (251), the extension plate (26) is also bent to be respectively matched, attached and fixed with the left side plate (22) and the right side plate (23) through the ninth crease line (261).

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