JP3460760B2 - Crease processing method for cardboard box material to improve bending dimensional accuracy - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ruled line processing method for a corrugated cardboard box blank (blank sheet) for improving bending dimension accuracy.

[0002]

2. Description of the Related Art Corrugated board is a thick structure in which a liner is bonded to one or both sides of a corrugated core. Therefore, in order to assemble the box at a right angle and to bend the box length, width, depth, etc. exactly according to the design dimensions, corrugated board is preliminarily processed with creases called ruled lines. The ruled lines include a score ruled line that is inserted at right angles to the corrugated board direction and a crease ruled line that is inserted parallel to the corrugated direction. Each ruled line is used for the same purpose, and is usually processed by applying a compressive force with a ruled line piece or the like from the vertical direction of the corrugated board.

By the way, when a box is made of corrugated cardboard, it is necessary to form a box having an inner size by adding a slight clearance to the size of the contents to be packed. However, when the box is manufactured, the corrugated board may not be able to be folded at the position of the pre-inserted ruled line. When the folding position changes, the shape and size of the box become larger or smaller than the originally designed shape and size. Such instability of the box size causes a trouble during operation of the automatic packaging line.

[0004]

By the way, at present, the cause of the change in the folding position of the corrugated board is considered as follows. When cutting a cardboard into a predetermined shape, or when assembling a box from a blank that has been subjected to ruled line processing at the same time as printing, the position of the crease ruled line that is put in parallel to the direction of the steps is the top of the corrugated board, the step valley,
It enters a random position such as in the middle (see FIG. 9). The compression strength differs depending on the position where the ruled line is inserted. That is, the creases formed in the valleys of the step are more likely to be bent than the creases formed in the tops of the steps because stress is more likely to be concentrated. When the bending process is illustrated, first, as shown in FIG. 10A, the compression side, that is, the inner side is deformed by buckling (primary buckling) during bending. Further, up to about 120 degrees, the transition proceeds relatively smoothly and the bending progresses, but when the angle becomes larger than that, the seating surface starts to interfere as shown in FIG. 10B, and the degree of interference gradually increases. . When it further approaches 180 degrees, as shown in FIG. 10 (C), a new seat (secondary seat) is formed at a position about 10 to 15 mm away from the starting point (the first seat) when the first bending. Occurrence occurs, and that part is greatly deformed. Due to the generation of the new spot, the bending position changes as shown by the dotted line in FIG.
In addition, the tip end has a sharp shape like a bow of a ship and is bent. However, stress is not reliably concentrated on the ruled lines due to the effect of cardboard restoration and paper moisture absorption, so when folding the sheet, the bending start position shifts and the shape and dimensions of the box are The present inventors believe that the initially designed shape may be larger or smaller than the normal size.

The variation in the bending position tends to appear more markedly when the corrugated board is bent 180 degrees than when it is bent 90 degrees.

The present invention has been made in view of the above-mentioned problems of the conventional ones. No matter which position the ruled line enters, the bending position does not change (is not displaced), and the ruled line is bent. An object of the present invention is to provide a ruled line processing method for a corrugated board material (blank sheet), which is characterized in that stress is concentrated so that it can be easily folded at a fixed position.

[0007]

In order to achieve the above object, the present invention relates to a box material made of corrugated cardboard having a liner bonded to one or both sides of a core, and a crease ruled line in the step direction of the corrugated cardboard. When engraving, two parallel crease ruled lines ab and a'b 'are engraved in a relationship such that the engraving interval is narrower than the step pitch p, and both ends of the two crease ruled lines are engraved. It is characterized in that the portion is provided with a cut portion that is cut out so as to form a substantially arc shape. The arcuate cut portion is formed so as to straddle the two parallel crease ruled lines and extend beyond one of the ruled lines to the outside.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a case where the embodiment of the present invention is applied to an outer box for a back-in-box formed from a corrugated sheet blank will be described. A preferred embodiment of the outer box used in the present invention is, as shown in particular in FIG. 5, a single blank 10 formed from double-sided corrugated board.
By using 0, a rectangular bottom plate is formed substantially in the center thereof. Two sets of side plates 2 and 3 are formed on the four sides with the bottom plate as the center, and on either side of any one set of side plates,
The extension flap 12 is continuously provided. In FIG. 5, reference numeral 1 is a rectangular bottom plate defined by folds formed in four corners at substantially the center of the blank 100, and 2 and 2 are centered on the bottom plate 1 and are connected to the left and right sides through the folds. The pair of side plates 3 and 3 provided is a pair of side plates that are continuously provided around the bottom plate 1 through folding lines, and the side plates 3 and 3 are formed to be wider than the side plates 2 and 2. . On the extension of the side plates 2, 2, 3 and 3, inner flaps 4 and 4 and outer flaps 5 and 5 which are lids when assembled and used are connected in series. Incidentally, reference numeral 6 is a dismantling hand hole formed by cutting into one of the inner flaps 4. Further, reference numeral 7 indicates the other flap 5,
It is a fixing hole for the spout (SPOUT) provided in the inner bag defined by the cut-out machine hole. The outer box of the present invention is an extension flap 12 having a length S which is obtained by extending the left and right edges of the wide side plates 3 and 3 and combining the side plate 2 and the inner flap.
12 are provided. On each extension flap 12, four inner cylinder forming pieces 8 to 11 are sectioned and formed through parallel folds. By the way, the width of the inner cylinder forming piece 8 near the side plate 3 is formed to be half the width L of the side plate 2. Reference numeral 13 is a handling hole provided in the opposite side plates 3 and 3, which is provided in a substantially diagonal position by being offset to the left and right from the center line of the box as described later.

The above-mentioned outer box is assembled from a blank 100 by hand or by a machine as described below. First, while raising the side plates 2, 2 and 3 and 3 at right angles to the bottom plate 1, the inner cylinder forming piece 8 is moved to the side plates 2 adjacent to each other.
It is fixed to the inner surface of the unit. Further, thereafter, the inner tube forming piece 9 is bent over the inner tube forming piece 8 by 180 degrees via the folds ab and a′b ′ provided between the inner tube forming pieces 8 and 9, and the side plate 2 is formed. The inner cylinder forming pieces 8, 8 that are adjacent to each other on the inner side of the
9 and 9 are butted against each other so as not to form a gap, and the outermost inner cylinder forming piece 11 is integrally fixed to the inner surface of the wide side plate 3. Also at this time, the end faces of the inner cylinder forming pieces 11, 11 adjacent to each other on the inner side of the side plate 3 are butted against each other and joined so that there is no step or gap between them (the horizontal vertical cross section after fixation in FIG. 3). Is represented).

As described above, a back-in-box outer box having an octagonal inner cylinder 20 integrally provided inside the quadrangular outer box 21 is obtained (see FIG. 2). This box has a one-piece structure in which a quadrangular outer box and an octagonal inner tube can be bent and formed from a single sheet blank such as double-sided corrugated board. Further, the hypotenuse surface (inner tube forming piece 10) of the octagonal inner tube 20 is obliquely arranged at the four corners of the quadrangular outer box 21. FIG. 1 shows a state in which an inner bag 22 is housed inside an octagonal inner cylinder 20. The inner bag 22 is made of, for example, a flexible plastic film such as polyethylene or nylon, or a laminated film mainly containing these, and a spout 23 is provided at one end of the bag. This spout is used when the content liquid is discharged from the inner bag contained in the outer box or when it is dispensed. The cutout perforation hole 7 defined in the outer flap 5 is opened and fixed there.

[0011]

EXAMPLE In the process of bending and assembling the outer box and the inner cylinder from the corrugated board, as described above, the crease called a crease ruled line parallel to the flute of the corrugated board is made on the sheet blank in advance. . However, the position of the crease ruled line randomly enters the corrugated corrugated corrugated top, corrugated trough, or the middle thereof. Therefore, when the blank is bent, the blank may not be folded at a predetermined position. Therefore, the shape of the assembled outer box and inner cylinder, and the bending dimensions may change. This tendency remarkably appears when the blank is bent by 180 degrees, and the bending accuracy decreases. When the bending accuracy decreases, the inner cylinder forming pieces 8, 9
The end faces of the do not butt together well, and gaps or steps are created, causing the bag to rub and tear. In order to solve the problem that the corrugated cardboard sheet blank is not folded at a fixed position, the inventors of the present invention have made diligent research, and when performing corrugated line processing on the corrugated cardboard sheet, use the development view of FIG. 5 and the partially enlarged view of FIG. As can be seen, two crease ruled lines for bending by 180 degrees were inserted between the inner cylinder forming pieces 8 and 9 instead of one as in the conventional case. That is, two 180-degree bending crease ruled lines ab and a'b 'were put in parallel at an interval of 5 to 6 mm in the case of, for example, an A-foot (thickness of about 5 mm) and a step pitch of 8.42 mm. . And this ruled line a
By providing arcuate recesses (undercuts) 26 that can concentrate the bending stress at the time of bending the sheet blank at both ends of b and a′b ′, it was possible to eliminate the fluctuation of the bending position. Of.

The arc-shaped cut portions 26 are parallel to each other.
The creases are formed so as to extend over the crease ruled lines ab and a′b ′ of the book and to extend beyond one of the ruled lines a′b ′ to the outside.

If such a structure is adopted, the stress can be concentrated on one of the two ruled lines a'b 'when the corrugated board is bent, and the starting point of the bending surely becomes the ruled line a'b'. Then, since stress concentrates on the other ruled line ab, the inner cylinder forming pieces 8 and 9 can be easily bent by 180 degrees, and the bending position does not deviate as in the conventional case.

[0014]

As described above, according to the present invention, even if the position of the crease ruled line is any position such as the corrugated corrugated corrugated top, corrugated trough, or the middle thereof, the bending position does not change (shift or shift). In addition, when the box is assembled, the bending stress is concentrated on the predetermined ruled line portion of the corrugated board, and the corrugated board can be easily bent at a fixed position. As a result, there is an effect that the folding accuracy is improved, the instability of the box size can be eliminated, and the occurrence of troubles during the operation of the automatic packaging line can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a back-in box that has been subjected to a ruled line processing method according to the present invention, and is a view in which a top surface of an outer box is opened and an inner bag is exposed.

FIG. 2 is a perspective view of only an outer box in which an inner bag is removed from the back-in-box of FIG. 1, showing a state in which an octagonal inner cylinder is integrally formed inside a quadrangular outer box. .

FIG. 3 is a horizontal sectional view of an outer box.

FIG. 4 is a vertical sectional view of the outer box, showing a state in which the lid is closed.

FIG. 5 is a developed plan view showing an example of a sheet blank forming an outer box.

FIG. 6 is an enlarged view of a main part of the blank shown in FIG.

FIG. 7 is a cross-sectional view showing the relationship between the corrugated board corrugation and the positions of two crease ruled lines.

FIG. 8 is a diagram of the corrugated cardboard having the crease ruled line bent 90 degrees.

FIG. 9 is an explanatory view showing the relationship between the corrugated board corrugated line and the crease ruled line position.

FIG. 10 is an explanatory diagram showing a folding process when the cardboard box material is folded 180 degrees.

[Explanation of symbols]

100 cardboard blanks ab, a'b 'crease ruled line 26 Arc-shaped recess

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-335982 (JP, A) JP-A-50-20881 (JP, A) JP-A-8-258887 (JP, A) Jitsukaihei 3- 78717 (JP, U) JP-B-49-47548 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B31B 1/25 B31F 1/08-1/10 B65D 5/50 B65D 77/06

Claims (2)

(57) [Claims] 1. When engraving a crease ruled line in the step direction on a box material made of corrugated cardboard with a liner adhered to one or both sides of a core, the engraving interval is narrower than the step pitch p. Two crease ruled lines a parallel to each other
b, a'b 'are engraved, and the cut portion of the corrugated cardboard cut out so as to form a substantially arc shape is provided at both ends of the two crease ruled lines. A ruled line processing method in a material for a corrugated box to enhance it. 2. The corrugated cardboard box according to claim 1, wherein the arcuate cut portion is formed so as to straddle the two parallel crease ruled lines and extend beyond one of the ruled lines to the outside thereof. Ruled line processing method for material.