JP2000085032A - Method for reversely folding sheet in manufacturing box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reversely folding a sheet in manufacturing box by which press forming of a ruled line for reverse folding can be reasonably and accurately performed and the reverse folding can be surely performed. SOLUTION: In a punching mold 10 for forming simultaneously a ruled line for folding on a process for punching a flexible sheet material, a ruled line forming body 15 with a ruled line forming part 17 of a projected line with the approximately same width as a ruled line pressing edge 12 at a position facing to the ruled line pressing edge 12 existing at a position corresponding to reverse folding is arranged and a required position of a corrugated board sheet 130 is pinched and pressed by these ruled line pressing edge 12 and ruled line forming body 17 to form ruled lines a and a' on both surface and back face of the corrugated board sheet 130 and reverse folding is performed along the ruled line a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reversely folding a fold during box making using a flexible sheet material. More specifically, the present invention relates to a method for accurately forming a reverse folding ruled line on a surface opposite to a surface on which a ruled line is pressed. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reverse folding a sheet during box making so that the sheet can be reversely folded accurately without damaging a folded portion of the sheet by embossing.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a box as a packaging container using a flexible sheet material such as a paperboard or a corrugated cardboard sheet (hereinafter, referred to as a corrugated cardboard sheet for convenience), a blank of a corrugated cardboard sheet is punched. While cutting out in a predetermined shape with a cutting blade, a creasing line is used to form a creasing line or a folding line on the blank with a creasing blade, and the creasing or folding is performed along the creasing line to form a predetermined portion. The box is formed by gluing.

[0003] Such a pressing operation of a ruled line on a corrugated cardboard sheet can be performed from any direction by any punching method. Therefore, when the ruled line is bent to the embossed (inserted) side. Can form a box with almost no problem. However, the one-touch assembly type box (called one-touch box) for the box, and the body box in the combination box of the lid and the body box, are assembled into a box unless they are folded in the direction opposite to the side where the ruled line is put as a fold. Some are not in the form.

In order to emboss accurate and useful folding lines on a blank made of the corrugated cardboard sheet, FIG.
As shown in (a), a tape-shaped ruled line forming body 10 that forms a ruled line on a blank in cooperation with a ruled pressing blade 107.
0 is stuck on the board surface 105 of the receiving die. In the ruled line forming body 100 shown in FIG. 5A, two groove forming members 102 are fixed to the surface of a base sheet 101 in parallel at a constant interval. Is formed with a ruled groove 103. Base sheet 1
The back side of 01 is stuck on the receiving board 105 via the pressure-sensitive adhesive layer 104. As shown in FIG. 5B, when the sheet is creased in such a relation between the crease forming body 100 and the crease pressing blade 107, the corrugated cardboard sheet 130 is along the creased crease line (crease line) 131 as it is. Since it can be bent, it can be bent for box making with almost no problem. Usually, the folding along the fold line by the ruled pressing is called forward folding. On the other hand, bending in the direction opposite to the ruled portion is usually called reverse folding. Therefore, hereinafter, the process of bending in the direction opposite to the ruled side is referred to as reverse folding.

In general, as a ruled press for forming a fold for reverse folding, for example, as shown in FIG. 6, a tape-shaped ruled line formed by providing a single protruding strip 111 on a receiving board surface 105 is provided. The body 110 is adhered, and two ruled blades 108 are attached to the ridge 111 at predetermined intervals.
A method is employed in which a reversely-folded ruled line is stamped and formed on the back surface (during processing) of the corrugated cardboard sheet 130 so that 11 is positioned at the center between the two ruled pressing blades 108, 108.

[0006] Alternatively, a ruled blade and a cutting blade are alternately arranged in a punching-type ruled portion, and a corrugated cardboard sheet is punched to form a ruled line portion and a cut portion (not shown). A method is adopted in which a portion cut by a cutting blade preferentially facilitates reverse folding.

[0007]

As described above, the reverse folding of a ruled sheet requires much more complicated processing than the forward folding of a corrugated sheet. Have. In particular, there is a problem in forming a ruled line for forming a 45-degree reverse fold at the bottom of the one-touch box. The 45-degree reverse folding ruled line at the bottom of the one-touch box needs to be bent particularly accurately.

In general, as shown in a partially cutaway perspective view of a bottom part assembled in FIG. 7, a one-touch box 1 is formed by cutting a blank punched to a required shape and dimensions along a predetermined ruled line formed simultaneously by embossing. After gluing the adhesive margin piece 3 provided at one end of the body part 2 to the inner surface of the body part piece 2a at the opposite end, when assembling the bottom part 4, each body part piece 2a
(2b, 2c, 2d) of each of the bottom pieces connected to the body piece 2
a and the bottom piece 4 connected to the body piece 2c at the opposite position.
a and the bottom piece 4c are bonded to the adjacent bottom piece 4b and bottom piece 4d with a flap 4e or 4f connected to the bottom piece 4d via a 45-degree reverse folding ruled line A, and the box bottom is assembled by auto-locking. I have. Then, when transported to the packaging factory, as shown in FIG.
It is folded down at the reverse folding ruled line A point and transported in low bulk,
In the process of packaging the product to be packaged (product), the product is folded and opened to assemble the bottom, and the product is put inside the box and packaged.

For this reason, when assembling the one-touch box 1, the folding 4 formed on the bottom 4 thereof is used.
If the 5th reverse folding ruled line A is not properly pressed and folded, the automatic locking of the bottom does not work during the automatic assembly of the box, and the box assembly process and the next packaging process There is a problem in that the box falls over while being conveyed by the conveyor, which hinders the packaging operation.

The 45-degree reverse folding ruled line provided at the bottom of the one-touch box is basically provided so as to be folded at a diagonal position at 45 degrees from two corners of the box. Generally, the dimensions of the box are designed and manufactured by the internal method according to the storage volume of the article to be packaged. For this reason, as shown in FIG. 7, one of the body pieces 2a spreads out at the bonding position by the sheet thickness t of the glue margin piece 3 of the body 2 at the bonding position. . For this reason, at the time of assembling, one bottom piece 4b is pulled out to the lock portion B of the bottom 4 by the thickness of the glue margin piece 3 and, in general, the right angle square At present, it has not been formed. Therefore, in order to exhibit the auto-lock function of the bottom part 4, the above-mentioned excessive engaging force is absorbed within the allowable range of the deformation of the material sheet at the engaging part (lock part B), or the dimension of the engaging part is largely cut. It has been assembled in a compromise, such as to facilitate assembly. However, in order to assemble by performing such a process, the accurate 45-degree reverse folding rule A
If not bent on the basis of the above, there is a problem that an excessive engagement force is generated and auto-locking becomes difficult.

Of course, the bending angle may be set to 45 degrees or more by the sheet thickness of the glue margin portion. However, if the inclination angle is set to an angle corresponding to the sheet thickness, the angle becomes irregular. Setting the upper angle is cumbersome. In particular, since the thickness differs depending on the type of corrugated cardboard sheet, the bending angle must be calculated and derived each time, and even if the angle can be calculated, the angle is accurately reflected on the planting of the creasing blade in the punching die. Making it impractical is not practical. Therefore, there is no other choice but to form the 45-degree reverse folding ruled line by pressing the 45-degree reference.

However, in the case of a conventional reverse folding ruled line formed by embossing, for example, in the case of forming a ruled line portion and a cut portion alternately, according to a corrugated cardboard sheet having a large thickness dimension,
If it is folded at 180 degrees during folding, the cut portion is too thin, causing a body hit phenomenon. The body contact phenomenon is a phenomenon in which since the folded corrugated cardboard sheet has a thickness, the insides of the corrugated cardboard sheets come into contact with each other to generate resistance. Therefore, it cannot be accurately bent by being deformed at the bent portion. In addition, in the case of a small box, when external pressure is applied with a strong force, if there is a cut part in the reverse folding part, the strength decreases because the constituent fibers of the corrugated cardboard sheet are cut at that part, May be cut. In particular, the 45-degree reverse folding ruled line formed at the bottom of the one-touch box is stamped diagonally across the corrugate forming the core of the corrugated cardboard sheet.

Further, as described above, the two-line ruled blade 10
In the embossing of the reverse folding ruled line by the combination of the ridges 8, 108 and the ridges 111 (see FIG. 6), the corrugated cardboard sheet 130 is formed by locally bending the corrugated cardboard sheet 130 by the ridges 111 and the two ridges 108. Therefore, a large stress is generated in the corrugated cardboard sheet material, which leads to a decrease in strength. In this case, there is a problem that a large box does not cause a problem, but a small box often breaks.

As described above, the box forming process in which a reverse folding ruled line is formed by stamping and bending at a place having a bad condition such as a one-touch box is required to have high processing accuracy. At present, there is a product loss that a product equivalent to% fails and cannot be used, and there are various troubles to solve it.

The present invention has been made in order to solve such a problem, and it is possible to easily and accurately form a reverse folding ruled line on a sheet material without performing complicated processing. It is an object of the present invention to provide a method of reverse folding a sheet during box production, which can surely reverse the folding.

[0016]

Means for Solving the Problems and Action / Effect In order to achieve the above-mentioned object, a method for reverse folding a sheet in box making according to the present invention is to simultaneously fold a crease in a step of punching a flexible sheet material. Is formed by a punching die,
A ruled line forming body having a ridged ruled line forming portion having substantially the same width as the ruled pressing blade is disposed at a position opposite to the ruled pressing blade at the reverse folding corresponding position, and the ruled blade and the ruled line forming body are used. A required portion of the flexible sheet material is pinched to form folding ruled lines on both sides of the flexible sheet material, and reverse bending is performed along the folding ruled line.

[0017] By doing so, the ruled line is formed by punching the ruled blade and the convex ruled line forming body from both the front and back sides at important points of the blank formed by punching from a flexible sheet material (corrugated cardboard sheet). Is pressed and formed, so that the core of the corrugated cardboard sheet is pressed and deformed to the middle portion of the thickness together with the liner portion in the ruled line forming portion, and the same plastic deformation is applied to both sides. Therefore, even when the sheet is reversely folded, only one of the liners (the surface layer) is not greatly pulled, and the liner (the surface layer) on the side to be bent is not greatly compressed. As a result, accurate bending becomes possible.

From the above, according to the present invention, in forming the 45-degree reverse folding ruled line at the bottom of the one-touch box, the corrugated cardboard sheet is ruled obliquely with respect to the corrugated peak (ruled line stamping). Can accurately and reliably form ruled lines, and if the lock part is treated according to the thickness of the glue margin part, product loss can be eliminated and the right angled box can be mass-produced. The effect is obtained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of a method for reversely folding a sheet during box making according to the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view showing the relationship between a ruled line forming body and a ruled press blade according to a process of performing the reverse bending method of a sheet during box making according to the present invention.

As shown in FIG. 1, a punching die 10 in which a ruled line is pressed simultaneously with punching in a punching process is provided with a ruled pressing blade 1 implanted on an upper die plate 11, for example.
Opposite to 2, the lower mold (receptacle) at the carved portion of the reverse folding ruled line
A ruled line forming body 15 having one ridge is stuck and arranged on 13.

As shown in an enlarged sectional view of FIG. 2, the ruled line forming body 15 has a ruled line forming portion having a required width which can prevent the meandering and can be stuck and fixed in a stable state. The pressure-sensitive adhesive layer 18 is provided on the back surface of the base 16, and the pressure-sensitive adhesive layer 18 is covered with a release paper 19 when not in use. When the ruled line forming body 15 is not used, a ruled line setting guide 20 having an H-shaped cross section is detachably attached to the ruled line forming portion 17. It can be stuck on top.

The ruled line setting guide 20 has a fitting groove 21 of the ruled line forming portion 17 and a set groove 22 having a width substantially equal to the thickness of the ruled blade at a position opposite to the groove 21 on the same axis in cross section. . Then, the fitting groove 21 is fitted into the ruled line forming portion 17 of the ruled line forming body 15, and the ruled line setting guide 20 is attached to the upper surface of the ruled line forming body 15 in the length direction by a joining tape 25 such as a cellophane tape. Have been able to maintain.

In order to use such a ruled line forming body 15, as shown in FIG. 3, the cutting edge of the ruled pressing blade 12 is inserted into the set groove 22 of the ruled line setting guide 20, and in this state, the ruled line forming body 15 is formed. In a state where the release paper 19 on the back surface of the base 16 is removed and the pressure-sensitive adhesive layer 18 is exposed,
By pressing the upper die plate 11 on which the 2 is mounted against the lower die (receiving plate) 13 board surface (when the lower die is movable, the lower die plate surface is pressed against the stationary ruled line forming body, and when the upper die is movable, Actuating the reverse), the ruled line forming body 15 is attached to the board surface of the lower die 13. Thereafter, when the lower mold 13 or the upper mold 11 is retracted, the ruled line setting guide 20 is separated from the ruled blade 12 and is left on the ruled line forming body 15. Therefore, by subsequently lifting and removing the ruled line setting guide 20, the ruled line forming body 15 is set on the board of the lower die 13 at a position matching the ruled blade 12.

When the ruled line is formed on the corrugated cardboard sheet 130 by the ruled line forming body 15 installed on the board of the lower die 13 and the ruled pressing blade 15 of the upper die 11, the reverse folded ruled line shown in FIG. As shown in the cross-sectional view of the attached cardboard, at the creased location of the cardboard sheet 130,
A ruled line a by the ruled line forming unit 17 and a ruled line a 'by the ruled blade 12 are simultaneously stamped and formed on the back surface. The corrugated sheet 13
0 is strongly compressed from both the front and back surfaces and is crushed and deformed in a linear shape, so that the fiber forming the corrugated cardboard sheet 130 is not cut off at the ruled line forming portion as in the related art. Only the shape of the liner portion forming the sheet is deformed. Therefore, the strength of the bent portion of the corrugated cardboard sheet does not decrease.

Since the corrugated cardboard sheet is creased from both the front and back sides to form a reverse folding ruled line, the 45 ° reverse folding ruled line A at the bottom 4 of the one-touch box 1 as described above.
As shown in FIG. 7, even when the corrugated sheet of corrugated cardboard is embossed diagonally, the core of the corrugated sheet is reliably compressed and deformed from both sides in the embossed portion, and is accurately crimped.
Therefore, the folding operation can be easily performed along the reverse folding ruled line, and the folding operation can be accurately performed. Therefore, when the bottom portion 4 is assembled in the one-touch box 1, the automatic locking at the lock portion B can be reliably performed. All problems can be solved.

As described above, the reverse bending method of the present invention is more effective when applied to a bottom portion of a small box having a short depth of a body portion in a one-touch box as described above. Further, it is also effective to employ a combination box with a lid and a body box with a reverse folding ruled line such as a body combination flap (not shown) of the body box. In the above description, a paper container using a corrugated cardboard sheet has been described. However, it goes without saying that the present invention can be applied not only to a corrugated cardboard sheet but also to a paper container made of cardboard.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view illustrating a relationship between a ruled line forming body and a ruled pressing blade according to a process of performing a reverse bending method of a sheet during box making according to the present invention.

FIG. 2 is an enlarged sectional view of a ruled line forming body.

FIG. 3 is a diagram illustrating a mode in which a ruled line forming body is installed on a lower die (receptor) of a punching type.

FIG. 4 is an enlarged cross-sectional view of a main part of a corrugated cardboard sheet in which reverse folding ruled lines are stamped.

FIG. 5 is a diagram showing a conventional forward folding ruled pressing means, in which (a) shows a relationship between a ruled line forming body and a ruled blade;
(B) is a cross-sectional view of the corrugated cardboard sheet that has been pressed.

FIG. 6 is a diagram illustrating a form of forming a reverse folding ruled line by using a ruled line forming body having a ridge and two ruled blades;

FIG. 7 is a partially cutaway perspective view showing the bottom of the one-touch box.

FIG. 8 is a perspective view showing a bottom portion of the one-touch box in a folded state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 One-touch box 2 Body 3 Glue margin piece 4 Bottom 4a, 4b, 4c, 4d Bottom piece 4e, 4f Flap 10 Punching die 11 Upper die plate 12 Ruled blade 13 Lower die (receiving board) 15 Ruled line forming body 16 Ruled line Base of formed body 17 Ruled line forming portion 18 Pressure-sensitive adhesive layer 20 Ruled line setting guide 21 Fitting groove 22 Set groove 130 Corrugated cardboard sheet A, a Ruled line (reverse folded ruled line) a 'Ruled line B Lock portion

Claims (1)

[Claims] 1. A punching die in which a folding ruled line is formed at the same time as a step of punching a flexible sheet material. A ruled line forming body having a ruled line forming portion of a strip is provided, and a required portion of the flexible sheet material is nipped by the ruled pressing blade and the ruled line forming body. A method of reverse folding a sheet at the time of box making, wherein a folding ruled line is formed and reverse folding is performed along the folding ruled line.