JP2002067191A - Corrugated cardboard sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently make a box from a corrugated cardboard sheet by a box making machine, by accurately performing the folding from a rule. SOLUTION: The linear groove-shaped rule processed to the corrugated cardboard sheet is formed so as to have an oblong rectangular cross section wherein the groove width of the rule is larger than the depth thereof and the inner corner parts on both sides of the groove bottom of the rule are formed to the folded parts of the corrugated cardboard sheet parts holding the rule and, even if one corrugated cardboard sheet part is largely folded from one inner corner part and the other corrugated cardboard sheet part is largely folded from the other inner corner part until both parts are overlapped with each other, both corrugated cardboard sheet parts are accurately folded without changing folding points.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a cardboard sheet which can be bent accurately from a ruled line portion.

[0002]

2. Description of the Related Art A corrugated cardboard sheet provided with a plurality of ruled lines and slots at predetermined positions is constructed by folding from these ruled lines. As shown in FIG. 9, the cross-sectional shape has a structure in which an extremely fine slit portion 22 having a width of about 1 mm is formed over the entire length at the center of the bottom of the narrow groove portion 21.

[0003] The ruled line of the cardboard sheet A
As shown in FIG. 10, the shape of the pair of upper and lower creaser rings 31 and 32 in the processing machine for processing 20 is such that the center of the outer peripheral end surface of the lower creaser ring 32 has Formed on the pressing surface 33 of the shape, and a structure formed by continuously forming an ultra-fine ridge portion 34 of about 1 mm over the entire circumference at the center of the pressing surface 33 in the width direction,
The ruled line 20 is processed on the cardboard sheet A by the pressing surface 33, and the slit portion 22 is processed by the extra fine ridge portion.

[0004]

However, when the corrugated cardboard sheet A is bent from the above-mentioned ruled line 20 in which a very narrow slit portion 22 is formed at the center of the groove bottom of the narrow groove portion 21,
As shown in FIG. 11, the cardboard sheet portions A ₁ and A ₂ on both sides of the slit portion 22 are gradually bent with the extra-fine slit portion 22 as a bending starting point, and these sheet portions A ₁ , both sides of the open end of the narrow groove portion 21 in the border 20 until the a ₂ are folded at right angles to each other, i.e., opposing portion a ₁ of the sheet portion a _1, a ₂ across the border 31, a ₂ but abuts, when folded to a further 90 ° to 180 ° from this state, the opposing portions a _1, a ₂ of the both side sheet portion a _1, a ₂ is crushed by each other and pressed together.

[0005] This crushing is not necessarily performed uniformly. One of the opposing portions is crushed more than the other by the strength of the opposing portions a ₁ and a ₂ of the sheet portions A ₁ and A _2. Accordingly, the bent portions of the sheet portions A ₁ and A ₂ move from the slit portion 22 to the crushed portion side. Therefore, one sheet portion becomes shorter in width by the movement than the other sheet portion, and the other sheet portion becomes longer than the one sheet portion by the movement. In such a case, there is a problem that accurate folding cannot be performed, the box becomes distorted, the flap becomes difficult to fold, and the automatic box making machine stops.

[0006] The present invention has been made in view of such problems, and an object of the present invention is to make it possible to bend accurately from a ruled line, and to make the box reliably and efficiently at the time of the next step of manufacturing. To provide a corrugated cardboard sheet.

[0007]

In order to achieve the above object, a cardboard sheet according to the present invention is a cardboard sheet in which a plurality of ruled lines and slots are formed at predetermined locations. The groove width of the ruled line is formed to be larger than the groove depth, and one of the inner corners at the inner corners on both sides of the groove bottom of the ruled line is folded along one of the cardboard sheet portions connected to the inner corner. It has a structure in which it is formed in a curved portion, and the other inner corner portion is formed in a bent portion of the other cardboard sheet portion connected to the one cardboard sheet portion via a ruled line.

[0008] In the cardboard sheet, claim 2
According to the invention, the depth of the groove bottom of the ruled line is formed to be approximately half the thickness of the cardboard sheet.

[0009]

When the cardboard sheet portions on both sides of the ruled line are bent from the ruled line portion, one sheet portion is bent with one of the inner corners at the inner corners on both sides of the groove bottom of the ruled line bent. The other sheet portion is bent using the other inner corner at both inner corners of the groove bottom as a bent portion. At this time, since the groove width of the ruled line is formed larger than the groove depth, even if the sheet portions on both sides are bent until they are at right angles to each other, the facing portions of these sheet portions facing each other across the ruled line abut. It is possible to bend accurately with each bent portion as a fulcrum.

Further, even if the opposite portions come into contact with each other when the sheet portions on both sides are largely bent via the ruled line, these sheet portions are not bent from one common bent portion but are fixed at a fixed interval. Since the two sheet portions are bent from the two bent portions, and the opposite sheet portions are bent from 90 degrees to a large angle overlapping each other when the opposing portions come into contact with each other, the crushing force after the contact of the opposing portions is reduced. It acts largely in the thickness direction of the corrugated cardboard sheet and hardly acts in the width direction, that is, the direction in which the bent portion is displaced, and can be accurately bent with both the bent portions as fulcrums as described above.

According to a second aspect of the present invention, the folding of the sheet portions on both sides through the ruled line is such that the groove bottom depth of the ruled line is formed to be approximately half the thickness of the cardboard sheet. By doing so, it is performed more reliably and accurately.

Therefore, when the cardboard sheet having such a ruled line is supplied to an automatic box making machine to make a box,
The sheet portions on both sides sandwiching the ruled line are accurately bent, so that a highly accurate cardboard box can be efficiently manufactured.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a cardboard sheet according to the present invention; FIG. The two straight bent portions 7 and 8 parallel to the long side of the cardboard case with a space equal to the height of the body of the cardboard case when manufactured by the box making machine are formed at both ends on the short side. Between the straight bent portions 7 and 8, the front and rear ends reach the straight bent portions 7 and 8, and the body portion is bent into a plane square shape. Straight groove-shaped ruled lines 1A, 1B, which become curved parts
1C is formed for each width interval of each peripheral wall of the body.

Further, at the portion between the front edge of the cardboard sheet A and the front straight bent portion 7 and at the portion between the rear edge of the cardboard sheet A and the rear straight bent portion 8, The front slotters 2A, 2B, 2C and the rear slotters 3A, 3B, 3C reaching the front and rear edges of the corrugated cardboard sheet A in the extending direction of the front and rear ends of the respective ruled lines 1A, 1B, 1C are respectively formed, and the front slotter 2A is formed. 2C, a portion between the front edge and the front straight bent portion 7 in the cardboard sheet A is divided into four front flaps 4A to 4D, and the above-mentioned parts in the cardboard sheet A are separated by rear slotters 3A to 3C. The portion between the rear edge and the rear straight bent portion 8 is divided into four rear flaps 5A to 5D. In addition, 9 is a glue margin piece formed in a protruding state on one side edge of the cardboard sheet A.

Although the shape of the cardboard sheet A is well known, the present invention relates to
It is characterized by the shape and structure of 1A-1C. That is, each of the ruled lines 1A to 1C is formed by providing a linear groove on the inner surface side of the cardboard sheet A. As shown in FIG. 2, each of the ruled lines 1A to 1C has a groove width. Is formed from a rectangular groove having a horizontally long cross section that is formed larger than the depth of the groove, and the inner corners on both sides facing each other with a groove width at the bottom of the groove, on both sides of the ruled lines 1A to 1C These are formed at the bent portions 10 and 11 of the cardboard sheet portions A ₁ and A ₂ , respectively.

[0016] The both side cardboard sheet portions A _1, A ₂ of the opposite end faces 13 and 14, Yes is formed by opposing groove wall surface borders 1A~1C consisting linear grooves, these sides cardboard sheet portions A _1, A ₂ is integrally continuous with a thin portion 15 between the groove bottoms of the ruled lines 1A to 1C and the outer surface of the cardboard sheet A. Then, the bent portion 10 of one of the cardboard sheet portions A _1, is formed by a corner portion in which and the end face 13 and the groove bottom of the corrugated cardboard sheet portion A ₁ are continuously arranged substantially at right angles, the other The bent portion 11 of the cardboard sheet portion A ₂ is
Are formed by corner inner and the end face 14 and the groove bottom of the corrugated cardboard sheet portion A ₂ are continuously arranged substantially at right angles. Note that both sides of the cardboard sheet portion of the depth of the groove bottom borders 1A~1C from cardboard sheet A of the bent portions 10 and 11 to a depth of approximately 1/2 of the thickness A _1, A ₂ To ensure that it can be bent. Also, if cuts are made in the ridges of the inner corners on both sides forming the bent portions 10 and 11, both the cardboard sheet portions A ₁ and A ₂ on both sides can be reliably and smoothly bent.

Thus, the ruled lines 1A to 1C and the front and rear slotters 2A to
The cardboard sheet A on which the 2C, 3A to 3C, the linear bent portions 7, 8 and the glue surplus piece 9 are processed is sent to the box making machine in the next step. In this box making machine, as shown in FIG. 3, the cardboard sheet A has left and right ends along the left and right ruled lines 1A and 1C such that the openings of the grooves of the ruled lines 1A and 1C are inside. The glue margin 9 protruding from one side edge of the corrugated cardboard sheet A and the other side end of the corrugated cardboard sheet A are folded by approximately 180 °, and are adhered and integrated.

At this time, for example, when the cardboard sheet portions A ₁ and A ₂ sandwiching the ruled line 1A are bent from the ruled line 1A, the cardboard sheet portions A ₁ and A ₂ are formed on both sides of the groove bottom of the ruled line 1A. Each of the bent portions 10 and 11 formed by the corner portions is bent. Then, since the larger than the groove depth of the groove width of the ruled line 1A, as shown in FIG. 4, both sides of the cardboard sheet portions A _1, A ₂ are each bent portion 1
Be folded up at right angles to each other as point bending 0,11, these facing each other across the border 1A cardboard sheet portions A _1, A ₂ of the corner portion 13a of the facing end surface 13, 14, 14a
Without abutting, and therefore, without being crushed by each other, the thin portion 15 between the groove bottom of the ruled line 1A and the outer surface of the cardboard sheet A is bent outward with the respective bent portions 10 and 11 as fulcrums. Can be bent accurately

From this state, the cardboard sheet portions A ₁ and A ₂ on both sides of the ruled line 1A are further separated from the bent portions 10 and 11 by 180 °.
Until it overlaps with each other, that is, as shown in FIG.
As shown in the figure, the facing end faces of the cardboard sheet portions A ₁ and A ₂
The corners 13a and 14a of the parts 13 and 14 come into contact with each other, but after the contact, the acting force for crushing the corners 13a and 14a acts intensively in the thickness direction of the cardboard sheet A, that is, in the width direction, that is, The cardboard sheet portions A ₁ and A _{2 on} both sides are accurately bent with the bent portions 10 and 11 serving as fulcrums as described above.

Such an accurate folding from the ruled line 1A is similarly performed on the other ruled lines 1B and 1C. From the folded state shown in FIG. 3, as shown in FIG. , Open from 1C so that the bending angle becomes 90 °, and bend 90 ° along the crease line 1B in the form of a mountain fold along the ruled line 1B, and then make the flaps 4A-4D, 5A-5D
To make a cardboard case. At this time, since the corrugated cardboard sheet A is accurately and reliably bent along the ruled lines 1A to 1C and is formed in a rectangular cylindrical shape, the flaps 4A to 4D and 5A to 5D also prevent each other from bending. It can be smoothly and reliably folded inward without occurrence of such a situation.

Next, the ruled lines 1A to 1C and the slotter
A processing machine for manufacturing a cardboard sheet A provided with 2A to 2C and 3A to 3C will be described with reference to FIG. 7. This processing machine is the same as the conventional processing machine shown in the figure and a pair of upper and lower creasers provided with ruled lines 1A to 1C. Except for the shapes of the rings 31 and 32, they are all the same. That is, an upper slotter shaft 37 equipped with a pair of upper and lower creaser rings 31A, 32A for processing the ruled lines 1A to 1C on the cardboard sheet A and cutting blades 35, 36 for processing the slotters 2A to 2C, 3A to 3C. And a lower slotter shaft 38 disposed below the upper slotter shaft 37.

In the pair of upper and lower creaser rings 31A and 32A, the outer peripheral surface of the upper creaser ring 31A is formed as a flat pressing contact surface which presses against the corrugated cardboard sheet A in the same manner as in the prior art. Fig. 8 shows the creasing ring 32A.
As shown in the figure, a pressing strip portion 32B having a rectangular cross section for processing the above-mentioned ruled lines 1A to 1C is projected from the center of the outer peripheral surface over the entire circumference. This pressing strip
The height of 32B is formed to be about half the thickness of the cardboard sheet A, and the width is formed to be larger than its height and smaller than the thickness of the cardboard sheet A.
Then, the cardboard sheet A is formed by the pressing strips 32B.
Are formed on the inner surface side of each of the ruled lines 1A to 1C having the above-described cross-sectional shape. The other processing states are the same as those in the related art, and a detailed description thereof will be omitted.

[0023]

As described above, according to the cardboard sheet of the present invention, in a corrugated cardboard sheet in which a plurality of ruled lines and slots are formed at predetermined positions, the groove width of the ruled line is formed to be larger than the depth. And forming one inner corner at both inner corners of the groove bottom of the ruled line at a bent portion of one cardboard sheet portion connected to the inner corner,
Since the other inner corner is formed at the bent portion of the other cardboard sheet portion connected to the one cardboard sheet portion via a ruled line, the cardboard sheet portions on both sides sandwiching the ruled line are connected to the ruled line portion. When folded from one side, one sheet portion can be smoothly bent with one inside corner at both inside corners of the groove bottom of the ruled line as a bending point, and the other sheet portion can be folded at both sides inside corner of the groove bottom. The other inner corner of the portion can be smoothly bent as a bending point. In addition, since the groove width of the ruled line is formed larger than the depth, even if these sheet portions on both sides are bent to be at a right angle to each other, the opposing portions of these sheet portions opposed to each other with the ruled line interposed therebetween are formed. There is no abutment, and it is possible to bend accurately with each of the bent portions as a fulcrum.

Further, the sheet portions on both sides are drawn through the ruled lines.
Even if the sheet portions are folded to a large angle of 90 ° or more, that is, overlapped with each other, these sheet portions are not bent from one common bent portion, but the two bent portions having a fixed interval as described above. Since each of the bent portions is bent, even if a part of the facing portion of the sheet portion is crushed after the abutment, the bent portions do not shift, and the bending can be always accurately and smoothly performed from each bent portion.
In the bending mode of the sheet portions on both sides via the ruled line, the groove bottom depth of the ruled line is formed to be approximately half the thickness of the corrugated cardboard sheet. By doing so, it is possible to perform the operation more reliably and accurately.

Therefore, when the cardboard sheet on which such a ruled line is processed is supplied to an automatic box making machine and box making is performed,
The sheet portions on both sides sandwiching the ruled line are accurately bent, so that a high-precision cardboard case can be efficiently manufactured without any trouble in folding the flap.

[Brief description of the drawings]

FIG. 1 is a simplified perspective view of an inner side of a cardboard sheet,

FIG. 2 is an enlarged vertical sectional front view of a ruled line portion,

FIG. 3 is a simplified perspective view of a cardboard sheet bent from a ruled line,

FIG. 4 is an enlarged vertical sectional front view showing a state where both side sheet portions are bent at a right angle from a ruled line;

FIG. 5 is an enlarged vertical sectional front view in which both side sheet portions are folded from a ruled line to an overlapping state,

FIG. 6 is a simplified perspective view of a state in which a cardboard sheet is formed in a square tubular shape;

FIG. 7 is a simplified side view of a cardboard sheet processing machine,

FIG. 8 is an enlarged front view of a part of a creaser ring for processing a ruled line,

FIG. 9 is an enlarged vertical sectional front view of a ruled portion of a conventional cardboard sheet;

FIG. 10 is an enlarged front view of a part of a conventional creaser ring for processing a ruled line,

FIG. 11 is an enlarged vertical sectional front view in a state where it is bent from a ruled line portion.

[Explanation of symbols]

A cardboard sheet A _1, A ₂ cardboard sheet part 1A~1C borders 2A-2C, 3A-3C slotter 10, 11 on both sides bent portion

Claims (2)

[Claims] 1. A corrugated cardboard sheet in which a plurality of ruled lines and slots are machined at predetermined locations, wherein the ruled lines have a groove width larger than a depth, and have inner corners on both sides of a groove bottom of the ruled lines. In which one of the inner corners is formed at the bent portion of one of the cardboard sheet portions connected to the inner corner portion, and the other inner corner portion is connected to the one of the cardboard sheet portions through a ruled line. A cardboard sheet portion formed at a bent portion of the cardboard sheet portion. 2. The corrugated cardboard sheet according to claim 1, wherein the depth of the groove bottom of the ruled line is formed to be approximately half the thickness of the corrugated cardboard sheet.