JP4783316B2 - Box using hollow synthetic resin plate and manufacturing method thereof - Google Patents

Description

  The present invention relates to a box using a hollow synthetic resin plate, commonly called a plastic cardboard, and a method for manufacturing the same.

Plastic cardboard made of synthetic resin such as polypyropylene and the same cross section as paper cardboard has a harmonica-like hollow structure is excellent in durability, heat resistance, chemical resistance, sound insulation, etc. It is known for its excellent properties and is used as a material for boxes such as returnable boxes.
For example, in the structure of a returnable box that can be assembled or deployed as disclosed in Japanese Patent Application Laid-Open No. 2006-273352, one bottom plate, two end walls extending vertically from its short side, and two sheets extending left and right from its long side Each side wall of the two end walls extends from side to side and has a flap that overlaps the end of the side wall, and the two side walls have two sides other than the part that overlaps the end wall flap. In use, the two end walls and the two side walls stand vertically from the bottom plate, and the flap portions of the end walls are overlapped on both sides of the side wall and fixed with fixing means. An open box can be formed. On the other hand, when not in use, the fixing is released and both end walls and both side walls are flattened, so that the entire box has a substantially dog-shaped outline.
In the above fixing means, a detachable coupling structure is used, but when used in the form of a box, the flap and the side wall are overlapped before passing through wire stitches, metal rivets, resin rivets, metal pins, etc. The four flaps are welded and bonded to the side wall by heat or ultrasonic waves.
However, the above configuration has the following problems.
(1) Since the blank consists of one unfolded shape, a wooden pattern is required to make a blank from a sheet.
(2) The length of the flap serving as the joint allowance of the joint portion is required to be at least 40 mm.
In other words, the joint portion is usually inwardly folded, and the joint portion is extended to eliminate the inner step in order to prevent damage and backlash of the contents and to increase the pressure resistance. For this reason, the expansion | deployment dimension of a blank becomes large and the area (weight) of a use sheet | seat becomes large.
(3) As described above, metal parts are used for joints in the case of mechanical connection as described above. When using polypyropyrene for plastic cardboard, the same material is not used. In addition, decomposition and separation are necessary, and the environmental load is high. Furthermore, since the corners are only bent and gaps are formed, water leakage cannot be prevented.
On the other hand, in the case of welded bonding, ultrasonic welding has a hygienic problem because pinholes are generated in the hollow structure due to the vibration system, and dirt and water enter from the outside.
(4) For this reason, conventional products that cannot leak water cannot be produced, and it has been difficult to adopt them in the field of flower and pharmaceutical transportation.
On the other hand, as a method for treating the end face of a hollow synthetic resin plate, for example, JP 2000-190384 A is known.
In the above configuration, the end surface processing portion facing the opening groove of the hollow body synthetic resin plate is formed by forming a first molten groove and a second molten groove on the molten surface of the predetermined thickness by the molded hot plate and melting the molten surface. The surface is bent at right angles so as to close the opening groove from the second melt groove to form the first bent portion 5, and the second bent portion located at the tip of the first bent portion 5 is hollow. The synthetic resin plate is bent at a right angle at the position of the plate thickness, and the back wall surface of the second bent portion is formed by welding so that it is substantially flush with the front wall surface of the hollow synthetic resin plate. .
However, although the end surface can be processed in the above configuration, it cannot be applied as a configuration for welding two members.
Japanese Patent Laid-Open No. 2006-273352 See FIGS. 1 to 3 Japanese Patent Laid-Open No. 2000-190384 See FIGS. 1 and 2

The present invention was devised in view of the above circumstances, and its main problem is that it can be cut without using a wooden pattern by using three divided rectangular pieces as a blank, and each piece is different. It is possible to mold the material, and each piece is to provide a box that is sealed so that water does not leak by joining the edges using heat welding.
Another object of the present invention is to provide a box that uses plastic cardboard and is excellent in strength and durability.
Still another object of the present invention is to provide a method for easily producing the box.

In order to solve the above problem, the box invention of claim 1
In a box structure in which separated blanks made of hollow synthetic resin plates are bonded by heat welding,
A blank is composed of a bottom wall surface and a pair of first peripheral wall surfaces connected to both sides thereof, a first blank which is bent into a U-shaped cross section, and a peripheral portion between the bottom wall surface and the pair of first peripheral wall surfaces. And a pair of second blanks that become the second circumferential wall surface disposed,
In either one of the first blank and the second blank, a first thermal welding margin and a second thermal welding margin which are set to a predetermined width and extend in the vertical direction and the horizontal direction at the time of box forming are formed. Make a notch at the intersection,
The first heat welding allowance and the wall surface orthogonal to this and the second welding allowance and the wall surface orthogonal to this are melted from the surface side to form a pair of first and second fusion pieces,
One of the pair of first and second molten pieces is folded on the other and integrally welded.
In the invention of claim 2,
At the time of assembling the box, the eye directions of the first peripheral wall surface and the second peripheral wall surface are both arranged vertically.
In the invention of claim 3,
The first peripheral wall surface and the second peripheral wall surface are made of plastic corrugated cardboard having different colors or thicknesses.
In the invention of claim 4,
A second heat welding allowance and a first heat welding allowance are arranged through notches on both sides along the three sides of the second blank, the first heat welding allowance and the edge of the first peripheral wall surface, Two heat welding allowances and the edge surface of the bottom wall surface are melted to form two sets of first and second molten pieces, and the first molten pieces are folded and overlapped on the outside of the second molten piece to form columnar edges It is characterized by forming.
Next, in the invention of the box manufacturing method of claim 5,
In the manufacturing method of the box which heat-welds and separates the separated blanks which consist of a hollow synthetic resin board,
A blank is a first blank composed of a bottom wall surface and a pair of first circumferential wall surfaces connected to both sides thereof, and a second circumferential wall surface disposed along the periphery of the bottom wall surface and the pair of first circumferential wall surfaces. And a pair of second blanks,
In either one of the first blank and the second blank, a first thermal welding margin and a second thermal welding margin which are set to a predetermined width and extend in the vertical direction and the horizontal direction at the time of box forming are formed. Make a notch at the intersection,
Bending the first blank along each wall surface into a substantially U-shaped cross section,
Place the U-shaped edge of the first blank on the second peripheral wall surface,
The hot plate is pressed at an angle of about 45 degrees to the outer corners of the first heat welding allowance and the second welding allowance and the wall surface orthogonal thereto, and is melted to a predetermined thickness from the surface side to be the first and second The heat welding allowance is the first molten piece, the orthogonal wall surface side is the second molten piece,
The push plate is raised, the first molten piece is bent, and the second molten piece is overlapped and welded to form a box.
In the invention of claim 6,
A first thermal welding margin is formed on the side of the second blank that contacts the pair of first peripheral wall surfaces of the first blank, a second thermal welding margin is formed on the side that contacts the bottom wall surface, and a notch is formed at the intersection of both Is formed,
The cutout is aligned with a corner portion of the first blank that is bent into a substantially U-shaped cross section.
Furthermore, in the invention of claim 7,
The hot plate has a pair of heating surfaces that intersect at an angle corresponding to the angle of the corner to be welded on both sides of the central right angle portion;
Press the outer corners perpendicular to the first blank and the second blank, push the hot plate evenly, melt the part where the pair of heating surfaces are in contact with each other with equal thickness, It is characterized by being welded in layers.

The present invention can achieve the following excellent effects and is extremely useful.
(1) Since it consists of three divided rectangular pieces, it is only necessary to cut, and a wooden mold is unnecessary, and the plate cutting efficiency is excellent.
Since each piece does not need to be manufactured from the same sheet, it can be manufactured from an originally unnecessary portion such as a cut piece of another product.
(2) Each piece can be formed from sheets having different thicknesses, strengths, and colors according to the use of the box. As a result, it is possible to manufacture a box having different wall surfaces without requiring printing, and the box can be given distinctiveness.
(3) Since the edges of the pieces are joined using heat welding to form the corners of the box, the melted resin can be buried in the hollow structure to form the high-density corners. The strength of the body can be increased.
(4) Since the bonding structure is only heat welding, if polypropylene is used for the plastic cardboard, the product can be completely recycled.
(5) Since the corners of the box are joined by thermal welding, they can be sealed without any gaps, preventing entry of foreign matter and liquid leakage, and expanding the use of the box. Can do.
Moreover, in the manufacturing method of the said box, there exist the following effects further.
(6) The hot plate is pressed at an angle of about 45 degrees to the joining portion of the first blank and the second blank to form a pair of first and second molten pieces, and then the push plate is raised to remove the first molten piece. Since it bend | folds and overlaps and welds with a 2nd molten piece, a 2nd blank can be couple | bonded with a 1st blank with a simple process.

  In this invention, a box blank made of plastic corrugated cardboard is separated into a plurality of blanks, the edges of each blank are melted, and one of them is folded back and integrally heat-bonded, thereby having strength and being sealed. Realized the box.

Hereinafter, embodiments of the box of the present invention will be described with reference to the drawings.
As shown in FIG. 1 (a), the box 1 includes a rectangular first blank 2 in which a pair of first peripheral wall surfaces 21 facing each other with a bottom wall surface 22 sandwiched between the left and right sides in the figure, and FIG. 1 (b). As shown in FIG. 4, the box is composed of a pair of rectangular second blanks 3 that become the second peripheral wall surface 31 that is arranged orthogonal to the first peripheral wall surface 21 when the box is assembled.
In the illustrated example, the first blank 2 and the second blank 3 are rectangular when viewed from the plane, but one or both of them may be square when viewed from the plane.

  On the other hand, as illustrated in FIG. 13, the conventional product includes a first peripheral wall surface 21 ′, a bottom wall surface 22 ′, a second peripheral wall surface 31 ′, and a flap 32 ′ as a developed shape of the box. Since it consists of a single blank, a wooden mold for pressing is required to form the blank. In this embodiment, both the first and second blanks 2 and 3 are rectangular or square. It can be easily formed by cutting with a cutter or the like.

As described above, the first blank 2 and the two second blanks 3 are independent from each other, so that the degree of freedom of cutting is high with respect to the plastic cardboard sheet, and the first blank 2 is the same as the conventional product. There is no need to provide a flap piece 32 ′ that is bent from the two circumferential wall surfaces 31 ′ and overlaps the first circumferential wall surface 21 ′.
Therefore, in the case of a general 1100 mm x 1100 mm pallet box (inner dimensions 615 mm x 415 mm x 270 mm), 0.86 m ² is sufficient compared to 1.169 m ^{2 of the} conventional product when compared with the net size (use area). since suffice 0.95 m ² with respect to 1.315M ² also show conventional compared with gross dimension (when converted in a sheet width), can be reduced by about 30% the amount of said sheet, weight and cost You can go down.

The first and second blanks 2 and 3 can be formed by cutting from separate plastic cardboard sheets having different thicknesses, strengths, colors, and the like.
Moreover, since the 2nd blank 3 is small in dimension, it can also be shape | molded using originally unnecessary parts, such as a cutting piece of another product.

[First blank]
The first blank 2 uses “Dampla Ace” (registered trademark, manufactured by Toagokogyo Co., Ltd.) for the plastic cardboard sheet, and the eye direction “a” is the continuous direction of each wall surface as shown in FIG. The bottom wall surface 22 (width 625 mm × length 415 mm) is connected between the pair of first peripheral wall surfaces 21 and 21 (in the illustrated example, width 275 mm × length 415 mm) to form one rectangular shape. (Width 1175 mm × length 415 mm).
A ruled line 23 serving as a crease is formed between the first peripheral wall surface 21 and the bottom wall surface 22 of the first blank 2.

[Second blank]
The second blank 3 uses the “Dampla Ace” and is used as a set of two.
The eye direction b of the second blank 3 is perpendicular to the eye direction of the first blank 2 and is the vertical direction (vertical direction in the figure) when used, and will be described later from the lateral length L1 of the bottom wall surface 22. A slightly longer lateral length including the pair of first welding allowances 41 minutes (625 mm + 12 mm × 2 = 649 mm) L2 and a lateral length L3 of the first peripheral wall surface 21 include one second welding allowance 42 minutes It has a rectangular shape composed of a long vertical length (275 mm + 11 mm = 286 mm) L4, and is used to form the second peripheral wall surface 31.

[Notch]
In this embodiment, as shown in FIG. 2, notches 4 are formed at the corners on both sides of one side corresponding to the lateral length L <b> 1 of the bottom wall surface 22 of the second blank 3.
At the time of welding, the second circumferential wall 31 extends along the extension lines (illustrated by dotted lines) extending along the vertical and horizontal sides of the notch 4 and parallel to the respective edges of the second blank 3, and the outer side is the first and first sides. 2 welding allowances 41 and 42.
In the illustrated example, the width of the first welding allowance 41 including the bent portion is about 12 mm, and the width of the second welding allowance is about 11 mm. However, the present invention is not particularly limited to the above numerical values, and has the same dimensions. It may be.

[How to assemble the box]
The assembly of the box 1 will be described with reference to FIG.
First, the first blank 2 is bent in a U shape along the ruled line 23.
And the 1st blank 2 bent in the state where each wall surface 21 and 22 stood perpendicularly is placed on the 2nd blank 3 arranged horizontally.
At this time, positioning is performed so that the corner portion C2 of the first peripheral wall surface 21 and the bottom wall surface 22 is aligned with the corner portion C1 of the notch 4.

As a result, the second blank 3 has a second peripheral wall 31 that closes the inner U-shaped space formed by the first peripheral wall 21 and the bottom wall 22, and the outer sides of the first peripheral wall 21 and the bottom wall 22. The first and second heat welding allowances 41 and 42 extend in a width of about 11 mm.
Then, the first peripheral wall surface 21 and the first heat welding allowance 41 are arranged at a right angle to form the first outer corner 5A, and the bottom wall surface 22 and the second heat welding allowance 42 are arranged at a right angle to form a second. An outer corner 5B is formed (see FIGS. 4 and 6).

Therefore, the heat plate 6 and the pressing plate 7 are sequentially and uniformly pressed against the first and second outer corner portions 5A and 5B to perform heat welding.
That is, in the case of the illustrated example, the hot plate 6 has three right angle portions R1 to R3 excluding one right angle portion having a square cross section, and a pressing portion having heating surfaces 6a and 6b on both sides of the central right angle portion R1. 62 and an arm portion 61 coupled to the pressing portion 62 (see FIG. 6).
In the present invention, the shape of the hot plate 6 is not limited to the above-described embodiment. In short, the hot plate 6 has a pair of heating surfaces 6a and 6b crossing at an angle corresponding to the angle of the corner to be welded to the box. I just need it.

[First outer corner]
In the case of the first outer corner portion 5A, the central right-angle portion R1 is aligned with the corner portion of the first peripheral wall surface 21 and the first heat welding margin 41, and the first heating surface 6a is first heat welded. The first heating surface 6b and the second heating surface 6b against the first peripheral wall surface 21 and pushing the heating plate 6 downward at an angle of about 45 degrees and toward the corners as it is. 2 The portion where the heating surfaces 6a and 6b are in contact with each other is melted by about half of its thickness (see FIG. 6).

As a result, the first heat welding allowance 41 melts substantially half t4 of the thickness t2 of the first heat welding allowance 41 over the length from the end to the half width of the first peripheral wall surface 21. Then, the first molten piece 51 is formed by being melted into the hollow structure of the first heat welding allowance 41.
In addition, the first peripheral wall surface 21 melts approximately half t3 of the thickness t1 of the first peripheral wall surface 21 from approximately half the thickness of the first heat welding allowance 41 over substantially the same length as the first melt piece 51. Then, the second molten piece 52 is formed by melting into the hollow structure in the first peripheral wall surface 21 (see FIG. 7).
Here, the melted portion to be melted into the hollow structure is preferably in a range not exceeding half of the plate thickness.
Note that the portion 52a connected to the upper part of the second molten piece 52 is cut obliquely by the entry of the hot plate 6, but the portion 52a is filled with the resin melted when pressed by the push plate 7 described later.

The pressing plate 7 is used for shaping the molten piece heated by the hot plate 6 into a desired shape and solidifying the welded portion.
In the case of the illustrated example, the push plate 7 is formed of a rectangular block, and the surface is cooled by water cooling or the like, and the molten piece heated by the hot plate 6 is shaped and solidified while being cooled. Then, it may be heated.
The end face of the pressing plate 7 is set at a position where the surface of the first peripheral wall surface 21 hangs down. When the melting by the hot plate 6 is finished and the hot plate 6 moves backward, the push plate 7 starts to rise.
Then, the push plate 7 bends the first molten piece 51 to the outside of the first peripheral wall surface 21 while ascending, and then superimposes the first molten piece 51 and the second molten piece 52 without any gaps to heat them together. Weld and bond.
And the surface of the said joint location becomes a substantially identical surface with the other surface of the 1st surrounding wall surface 21 (refer FIG. 8).
Thus, the first columnar edge portion 50A having a high bulk density is formed along the first outer corner portion 5A (see FIG. 5).

[Second outer corner]
Similarly, as shown in FIG. 9A, the first heating surface of the hot plate 6 is arranged such that the central right-angled portion R1 is aligned with the second outer corner portion 5B of the bottom wall surface 22 and the second heat welding allowance 42. 6a is pressed against the second heat welding allowance 42, the second heating surface 6b is pressed against the bottom wall surface 22, and the heat plate 6 is pushed forward at an angle of about 45 degrees downward and toward the corners to make the first The portion where the second heating surfaces 6a and 6b are in contact with each other is melted by about half the plate thickness (see FIG. 9B).

As a result, the second heat welding allowance 42 melts substantially half of the thickness of the second heat welding allowance 42 over the length from the end to the width of approximately half the thickness of the bottom wall surface 22. The first molten piece 53 is formed by being melted into the hollow structure of the two heat welding allowance 42.
Further, the bottom wall surface 22 melts approximately half of the thickness of the bottom wall surface 22 from the position of approximately half the thickness of the first molten piece 53 over substantially the same length as that of the first molten piece 53, so The second molten piece 54 is formed by being melted into the hollow structure (see FIG. 8B).
The end face of the push plate 7 is set at a position where the bottom wall surface 22 hangs down, and starts to rise when melting by the hot plate 6 ends and the hot plate 6 moves backward.

The push plate 7 bends the first molten piece 53 to the outside of the bottom wall surface 22 while ascending, and then superimposes the first molten piece 53 and the second molten piece 54 without any gap, and heat-bonds them together. The surface of the joint portion is substantially flush with the front wall surface of the other bottom wall surface 22 (see FIG. 9C).
Thereby, the 2nd columnar edge part 50B with a high bulk density is formed along the 2nd outer side corner | angular part 5B (refer FIG. 5).

In this way, the first heat welding allowance 41 is folded and integrated on the outside of the first peripheral wall surface 21, and the second heat welding allowance 42 is integrated on the outside of the bottom wall surface 22 (lower side when completed). The box 1 can be formed by integrally connecting the second peripheral wall surfaces 31 to both sides of the pair of first peripheral wall surfaces 21 and 21 and the bottom wall surface 22 that open along the edges in the extending direction. it can.
By adopting the above configuration, the weight of the four flaps required in the conventional structure can be reduced (about 25% weight reduction), and the compressive strength can be improved by about 20% on average. The effect could be confirmed.
This is because the edge of the blank is joined using thermal welding to form the corner of the box, so that the melted resin is buried in the hollow structure to form a corner edge with a high bulk density, and By aligning the eye direction vertically.
FIG. 14 shows a graph comparing the compressive strength of the product according to the present invention and the conventional product.
The conditions of this compressive strength comparison test are as follows.
(A) Testing machine Compression testing machine manufactured by Shimazu Co., Ltd. DSS-2000
(B) Pretreatment Leave at a temperature of 26 degrees and 50% RH for 24 hours or more (c) Compression amount Compression speed 12.5mm / min Static plane compression load (d) Box condition No contents, top plate attached Perform a load test.

In the above embodiment, the notch 4 is formed in the second blank 3, and the first heat welding allowance 41 and the second heat welding allowance 42 are formed along the notch 4. However, as shown in FIG. The blank 2 may be provided.
In the first blank 2 of the second embodiment, both side edges of the first peripheral wall surface 21 slightly extend outward to form a first heat welding allowance 41 ', and both side edges of the bottom wall surface 22 slightly extend outward. The second heat welding allowance 42 'is formed in a substantially rectangular plate shape, and a square notch 4' is formed between the first heat welding allowance 41 'and the second heat welding allowance 42'. It consists of the illustrated example structure (refer Fig.10 (a)).
The second blank 3 is composed of a rectangular or square second peripheral wall surface 31.

Also in this case, as in the above embodiment, the first and second heat welding allowances 41 'and 42' and a part of the second peripheral wall surface 31 are a pair of hot plates (not shown) and less than about half of the thickness. Are melted to form first melt pieces 51 ′, 53 ′ and second melt pieces 52 ′, 54 ′. The first heat welding allowance 41 ′ and the second heat weld allowance 42 ′ are respectively formed on the second peripheral wall surface 31. They are welded so that they are bent along the outer side and are flush with the other second peripheral wall surface 31 (see FIG. 10C).
Details of the welding are shown in FIG. 11, but the configuration is the same as in FIGS.
Also in this case, as in the above-described embodiment, no gap is generated, and entry of dust or liquid or liquid leakage can be prevented.

[Other examples of box applications]
In the said Example 1, 2, since the 2nd blank 3 which forms the 2nd surrounding wall surface 31 is a different body from the 1st blank 2 which forms the 1st surrounding wall surface 21, the 1st circumference set up at the time of an assembly The eye directions a and b of the wall surface 21 and the second peripheral wall surface 31 can be aligned vertically, and the strength of the box 1 can be increased. However, in the present invention, one eye direction is horizontal as in the prior art. Or both eye directions may be horizontal.

Similarly, since the box is conventionally formed from the same sheet, its thickness, strength, color, etc. are the same and could not be changed.
Therefore, when an identifier is attached to the box itself or a specific wall surface, it is necessary to apply paint, print it, or attach a label.
On the other hand, in this invention, since the 2nd blank 3 used as the 2nd surrounding wall surface 31 is a different body, it differs from the 1st blank from the sheet | seat of the plastic cardboard from which thickness, intensity | strength, or a color differs. Since it can shape | mold, it becomes possible only by assembling the box 1 to change the thickness, intensity | strength, or color of the 2nd surrounding wall surface 31 of one or both.

In addition, when the first blank 2 and the second blank 3 are different in thickness, the thickness melted by the hot plate 6 is preferably such that it does not reach half of the thinner one.
Thereby, when the 1st fusion piece and the 2nd fusion piece are piled up, the piled up surface and other sides can be fabricated on the same surface.

Next, FIG. 12 shows an example in which the box 1 configured as described above is used as a passing box.
In this case, a fitting frame 71 made of polypropylene and a corner joint 72 are used.
In other words, the fitting frame 71 having a channel cross-section extending linearly along the upper end edges of the first peripheral wall surface 21 and the second peripheral wall surface 22 is inserted from above.
Then, a corner joint 72 having a channel cross section extending in an angle shape is externally fitted from above to a pair of fitting frames 71, 71 adjacent to each other at a corner portion of the box 1 in a right angle direction.
Then, the fitting frame 71 can be coupled to the corner joint 72 by spot welding for use.

In this way, all the materials are made of polypropylene, so that they can be recycled as they are.
The structure of the returnable box or container is not limited to the above embodiment, and other known structures can be used.
The box is not limited to a returnable box as described above, and the box 1 can be a C-type body and / or a separate cover.
In addition, by sealing the end face of the blank, the hollow structure eyes are closed at the end, so that a box that can prevent the intrusion of foreign substances can be manufactured, and a box that is compatible with HACCP (food safety and hygiene management technique). Can also be used.
In addition, it goes without saying that various design changes can be made without departing from the scope of the present invention.

It is the blank which comprises a box, Comprising: (a) is a top view of a 1st blank, (b) is a top view of a 2nd blank. It is an enlarged plan view of the second blank. This is the first step when assembling the first blank and the second blank. This is the second step. (A) is the 3rd process, (b) is a perspective view of the box which opened up. It is an expanded sectional view of the state before the start of the heat welding with a 2nd surrounding wall surface and a 1st surrounding wall surface. It is an expanded sectional view of the state which melted the heat welding allowance. It is an expanded sectional view of the state where the 1st fusion piece and the 2nd fusion piece were welded. It is an expanded sectional view which shows the heat welding of a 2nd surrounding wall surface and a bottom wall surface, Comprising: (a) is before welding, (b) is the molten state by welding, (c) is the welding state of a molten piece. It is a figure which shows the assembly procedure at the time of providing the heat welding allowance of Example 2 in the 1st blank, Comprising: (a) is a 1st process, (b) is a 2nd process, (c) shows a 3rd process. It is a perspective view. It is an expanded sectional view which shows the heat welding of the 1st surrounding wall surface (bottom wall surface) of FIG. 10, and a 2nd surrounding wall surface, Comprising: (a) is before welding, (b) is the molten state by welding, (c) is fusion | melting. It is the welding state of a piece. It is explanatory drawing in the case of the returnable box of Example 3, (a) is an exploded perspective view, (b) is an assembly drawing. It is a top view which shows an example of the blank of the conventional box. It is a graph which compares the compressive strength of the product which concerns on this invention, and a conventional product.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Box 2 1st blank 3 2nd blank 4, 4 'notch 5A 1st outside corner 5B 2nd outside corner 6 Heat plate 6a 1st heating surface 6b 2nd heating surface 7 Push plate 10 1st orthogonal part 20 Second orthogonal portion 21 First circumferential wall surface 22 Bottom wall surface 23 Ruled line 31 Second circumferential wall surface 41 First thermal welding margin 42 Second thermal welding margin 51 First molten piece 52 Second molten piece 53 First molten piece 54 Second molten Piece 61 Arm portion 62 Pressing portion 71 Fitting frame 72 Corner joint

Claims (7)

In a box structure in which separated blanks made of hollow synthetic resin plates are bonded by heat welding,
A blank is composed of a bottom wall surface and a pair of first peripheral wall surfaces connected to both sides thereof, a first blank which is bent into a U-shaped cross section, and a peripheral portion between the bottom wall surface and the pair of first peripheral wall surfaces. And a pair of second blanks that become the second circumferential wall surface disposed,
In either one of the first blank and the second blank, a first thermal welding margin and a second thermal welding margin which are set to a predetermined width and extend in the vertical direction and the horizontal direction at the time of box forming are formed. Make a notch at the intersection,
The first heat welding allowance and the wall surface orthogonal to this and the second welding allowance and the wall surface orthogonal to this are melted from the surface side to form a pair of first and second fusion pieces,
A box structure comprising one of the pair of first and second molten pieces folded to the other and integrally welded.   2. The box structure according to claim 1, wherein when the box is assembled, the eye directions of the first circumferential wall surface and the second circumferential wall surface are both arranged vertically.   The box structure according to claim 1, wherein the first peripheral wall surface and the second peripheral wall surface are made of plastic corrugated cardboard having different colors or thicknesses.   The second heat welding allowance and the first heat welding allowance are arranged through notches on both sides along the three sides of the second blank, the first heat welding allowance and the edge of the first peripheral wall surface, the second The heat welding allowance and the edge surface of the bottom wall surface are melted to form two sets of first and second molten pieces, and the first molten pieces are folded and overlapped on the outside of the second molten piece to form the columnar edge portion. The box structure according to claim 1, wherein the box structure is formed. In the manufacturing method of the box which heat-welds and separates the separated blanks which consist of a hollow synthetic resin board,
A blank is a first blank composed of a bottom wall surface and a pair of first circumferential wall surfaces connected to both sides thereof, and a second circumferential wall surface disposed along the periphery of the bottom wall surface and the pair of first circumferential wall surfaces. And a pair of second blanks,
In either one of the first blank and the second blank, a first thermal welding margin and a second thermal welding margin which are set to a predetermined width and extend in the vertical direction and the horizontal direction at the time of box forming are formed. Make a notch at the intersection,
Bending the first blank along each wall surface into a substantially U-shaped cross section,
Place the U-shaped edge of the first blank on the second peripheral wall surface,
The hot plate is pressed at an angle of about 45 degrees to the outer corners of the first heat welding allowance and the second welding allowance and the wall surface orthogonal thereto, and is melted to a predetermined thickness from the surface side to be the first and second The heat welding allowance is the first molten piece, the orthogonal wall surface side is the second molten piece,
Raise the push plate, bend the first molten piece, overlap with the second molten piece, and weld,
A method for manufacturing a box, comprising forming a box. In the second blank, a first heat welding allowance is formed on the side of the first blank that contacts the pair of first peripheral wall surfaces, a second heat welding allowance is formed on the side that contacts the bottom wall surface, and a notch is formed at the intersection of the two. Formed,
6. The box manufacturing method according to claim 5, wherein the notch is aligned with a corner portion of the first blank that is bent into a substantially U-shaped cross section. The hot plate has a pair of heating surfaces intersecting at an angle corresponding to the angle of the corner to be welded on both sides of the central right angle portion,
Press the outer corners perpendicular to the first blank and the second blank, push the hot plate evenly, melt the part where the pair of heating surfaces are in contact with each other with equal thickness, The box manufacturing method according to claim 5, wherein the box is welded in layers.

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