JPH10244488A - Rotary cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent folded wrinkles from occurring on a corrugated fiberboard in a rotary cutter which cuts a corrugated fiberboard by making the edge of a knife installed on the outer periphery of a knife rotor with the outer periphery of an anvil rotor. SOLUTION: A knife 6 is installed on the outer periphery of a knife rotor 1, and the edge 6a of the knife 6 can be brought in contact with the outer periphery of an anvil rotor 2 which is installed opposedly to the knife rotor 1. Also a sheet retainer 7a is installed at least on the preceding side in the rotating direction of the knife 6, and a corrugated fiberboard A is prevented from floating, by the sheet retainer 7a, in the range between a position where the knife 6 starts to contact the corrugated fiberboard A and a position where cutting is completed. Thus wrinkles are prevented from occurring due to folding of the corrugated fiberboard A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary cutter for cutting a corrugated cardboard into a predetermined length.

[0002]

2. Description of the Related Art In general, in a corrugator for producing corrugated cardboard, a slitter is provided on a transfer path of corrugated cardboard such as double-sided corrugated cardboard or double-sided corrugated cardboard continuously fed from a double facer, and a rotary cutter is provided downstream of the slitter. After cutting the corrugated cardboard to a required width dimension by using the rotary cutter, the corrugated cardboard is cut to a length specified by a rotary cutter.

[0003] Japanese Patent Application Laid-Open No. 50-160892 discloses a rotary cutter for cutting a corrugated cardboard into a prescribed length. In this rotary cutter, a knife extending in the longitudinal direction of the pair of knife rotors is attached to the outer periphery of each of the pair of knife rotors, and the pair of knife rotors are rotated in opposite directions to each other. The cardboard sent between the pair of knife rotors is cut.

[0004] Here, the knife may be mounted in parallel with the axis of the knife rotor, or may be mounted with a predetermined twist angle with respect to the axis. In the case of a knife rotor in which the knife is parallel to the axis, the cutting resistance is high, and a large load is applied to the knife rotor and its bearing. Therefore, a knife rotor with high rigidity is required, and the rigidity of the bearing must be increased. is there.

On the other hand, in a knife cylinder provided with a twist angle on a knife, the cutting position moves from one side of the cardboard to the other side when cutting the cardboard, so that the cutting resistance is small, and the knife rotor and the bearing part are hardly cut. The acting load can be reduced. Further, it has a feature that the corrugated cardboard can be cut smoothly.

For this reason, in many cases, the rotary cutter is attached to the knife with a twist angle.

In the above-mentioned rotary cutter, if the pair of knives is not completely rubbed, it is not possible to cut the corrugated cardboard with high accuracy. And it takes time and skill to change the knife. This problem is particularly remarkable when the knife has a twist angle.

Further, in order to maintain the accuracy of the cut edge, a driving unit of the knife rotor requires a high-precision gear unit without backlash or capable of adjusting backlash, which is disadvantageous in cost.

By the way, in a rotary cutter, the cutting length of the corrugated cardboard is shorter than the circumference of the knife rotor, or conversely longer than the circumference of the knife rotor. Therefore, the knife rotor is cut in accordance with the cutting length and the traveling speed of the corrugated cardboard. Speed control is performed during one rotation.

That is, when the cutting length is shorter than the circumference of the knife rotor, the knife accelerates after cutting the corrugated cardboard, then decelerates, and when the peripheral speed of the knife cylinder becomes equal to the traveling speed of the corrugated cardboard, the constant velocity is reached. It rotates to cut the cardboard. On the other hand, if the cutting length is longer than the peripheral speed of the knife rotor, the knife cuts the cardboard, decelerates it, stops it if necessary, accelerates it again, and rotates it at a constant speed when it becomes equal to the running speed of the cardboard, thereby cutting the cardboard. Is to be cut.

[0011] In either case, since it is necessary to control the speed of the pair of knife cylinders in synchronization, there is also a problem that the control device is complicated.

In order to solve the above-mentioned problems, in a rotary cutter disclosed in Japanese Patent No. 2511784, as shown in FIGS.
0 and the anvil rotor 21 are opposed to each other, and the knife rotor 2
The cutting edge 22a of the knife 22 provided on the outer periphery of 0 is brought into contact with the outer periphery of the anvil rotor 21 to cut the cardboard.

Since the rotary cutter has a configuration in which the cardboard is cut by the contact of the cutting edge of the knife 22 with the outer periphery of the anvil rotor 21, the cutting time is adjusted by bringing the cutting edge 22 a of the knife 22 into contact with the outer periphery of the anvil rotor 21. Unlike the rotary cutter, there is no need to grind a pair of knives, and the adjustment operation is easy, and the adjustment can be performed in a short time and during operation.

[0014] In addition, there are various features that the exchange of the knife is easy.

[0015]

By the way, in the rotary cutter shown in FIG. 4, wrinkles are apt to be formed near the cut edge of the corrugated cardboard, and there is a point to be improved in improving the commercial value.

That is, as shown in FIG. 6 (I), the knife 22 of the knife rotor 20 moving at a peripheral speed equal to the traveling speed of the corrugated cardboard A is positioned before a straight line connecting the center of the knife rotor 20 and the center of the anvil rotor 21. As the knife rotor 20 starts rotating and the knife rotor 20 rotates, the cutting edge 22a of the knife 22 pushes down the contact portion of the first liner a.

Therefore, a tensile force acts on the first liner a before and after the knife contact position toward the contact position. This pulling force increases as the cutting edge 22a of the knife 22 approaches the upper part of the outer periphery of the anvil rotor 21,
The pulling force tends to lift the knife abutment site.

Further, the position where the knife 22 pushes down the first liner a is upstream of the contact position between the anvil rotor 21 and the cardboard A, so that the cardboard A is located on the leading side portion A 'on the front side of the knife contact portion. As a result, an upward rotational moment easily acts.

As shown in FIG. 6 (II), when the knife 22 rotates to a position where the distance between the cutting edge 22a of the knife 22 and the outer periphery of the anvil rotor 21 becomes smaller than the thickness of the cardboard A, the knife contact portion of the cardboard A Is compressed and deformed, and the end of the leading side portion A ′ of the cardboard A is in a free state by the previous cutting, so that it is particularly easy to bend upward by the tensile force and the rotational moment.

At this time, since a downward load acts on the leading side portion A 'by its own weight, the leading side portion A' is bent near the knife contact portion, and wrinkles are generated at the bent position (a).

The corrugated cardboard A starts to be cut by the knife 22 from the state shown in FIG. 6 (II), and when the cutting edge 22a of the knife 22 rotates to a position where it comes into contact with the outer periphery of the anvil rotor 21 in FIG. 6 (III), The cardboard A is completely cut.

At this time, since the leading side portion A 'of the cardboard A is in a state where the portion close to the knife contact portion is inclined, the cutout b of the cardboard A is inclined as shown in FIG. 6 (IV).

As described above, the corrugated cardboard A is bent at the time of cutting, causing wrinkles, and the cut end b is inclined.
Since the product value is low and it is defective, there is a point to be improved.

An object of the present invention is to provide a rotary cutter for cutting a corrugated cardboard by bringing a blade edge of a knife attached to an outer periphery of a knife rotor into contact with an outer periphery of an anvil rotor.
It is to prevent the corrugated cardboard from being bent from the start to the end of cutting, and to obtain a highly accurate cut perpendicular to the side surface of the corrugated cardboard.

[0025]

In order to solve the above-mentioned problems, according to the present invention, a knife rotor and an anvil rotor opposed to the knife rotor are rotated in opposite directions to each other, so that the outer circumferential length of the knife rotor is increased. In the rotary cutter for cutting the corrugated cardboard transferred between both rotors in the width direction by the action of the blade edge of the knife extending in the direction abutting on the outer periphery of the anvil rotor, the corrugated cardboard is lifted at least on the leading side in the rotating direction of the knife. A structure with a sheet retainer to prevent this is adopted.

Here, the sheet retainer may be an elastic body such as sponge or rubber. A sheet guide slidably supported in the outer diameter direction of the knife rotor, and the sheet guide is connected to the outer diameter direction of the knife rotor. May be made of a combination of elastic bodies that press against each other.

[0027]

As described above, since the sheet press is provided on the leading side in the rotating direction of the knife, the lifting of the cardboard is prevented by the sheet press until the cutting edge of the knife starts to contact the cardboard and cuts the cardboard. can do. For this reason, the occurrence of wrinkles due to the bending of the corrugated cardboard can be prevented, and the corrugated cardboard can be cut in the state of a flat plate.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a first embodiment of a rotary cutter according to the present invention. As shown, an anvil rotor 2 is provided below the knife rotor 1. A pair of knife holders 3 are fixed to the outer periphery of the knife rotor 1 by tightening bolts 5 screwed into screw holes 4 of the knife rotor 1.

A knife 6 is mounted between the pair of knife holders 3. The knife 6 extends in the longitudinal direction of the knife rotor 1, and its cutting edge 6 a can contact the outer periphery of the anvil rotor 2.

Here, the knife 6 may be mounted parallel to the axis of the knife rotor 1, or may be mounted inclined with a predetermined twist angle with respect to the axis.

Sheet retainers 7a and 7b made of an elastic material such as sponge or rubber are attached to the leading and trailing sides of the knife 6 in the rotation direction. Sheet presser 7
a and 7b are such that the sheet pressing surface 8 on the outer diameter side is a cardboard A
At the time of cutting, the cardboard A may be lightly pressed, or may be such that a slight gap is formed between the cardboard A and the first liner a. In the case of mounting for pressing the cardboard A, the elastic force of the sheet retainers 7a and 7b is appropriately selected so that the cardboard A is not crushed.

That is, the sheet retainers 7a and 7b have a thickness (height) and an elastic force so as not to crush the corrugated cardboard A at the time of cutting and not to cause the folding. I just need.

The sheet retainers 7a and 7b may be long or short corresponding to the length of the knife rotor 1. In the case of short sheet holders 7a and 7b, a plurality of knife holders 1 are attached at a required interval in the longitudinal direction of the knife rotor 1.

As described above, by providing the sheet pressers 7a and 7b on the leading side and the trailing side in the rotating direction of the knife 6, the cutting edge 6a of the knife 6 is moved to the cardboard A as shown in FIG. From the position where the first liner a comes into contact with the first liner a until the cutting is completed as shown in FIG. 6 (III), the cardboard A is prevented from being lifted by the sheet pressers 7a and 7b, and the cardboard A is bent. Wrinkles can be prevented from occurring.

Further, since the cardboard A is cut by the knife 6 in the state of a flat plate, the cut end can be prevented from being inclined.

In the cutting step of the corrugated cardboard A, the upstream side (the trailing side) of the knife contact portion of the corrugated cardboard A is long and continuous.
As in the embodiment, the sheet presser 7 is also provided on the trailing side of the knife 6.
By providing b, it is possible to reliably prevent the downstream side of the knife contact portion of the cardboard A from being broken.

As in the first embodiment, the sheet retainers 7a and 7b are made of elastic material to prevent the cardboard A from being lifted up, so that the sheet retainers 7a and 7b have flexibility. And can be made cost effective.

FIG. 2 shows a second embodiment of the rotary cutter according to the present invention. In this embodiment,
Guide members 10a and 10b are arranged on the leading side and the trailing side in the rotation direction of the knife holder 3, respectively.
b is fixed by tightening a bolt 11 screwed into the knife rotor 1, and the guide space 1
2, and sheet pressers 7a and 7b are inserted into each guide space 12.

The sheet pressers 7a, 7b are
And a resilient member 14 for pressing the sheet guide 13 in the outer diameter direction of the knife rotor 1. The sheet guide 13 has a protrusion 15 provided at a rear end thereof. , Are prevented from coming off by the engagement of the protrusions 16 provided at the distal ends of the knife holder 3 and the guide members 10a and 10b, and are slidable by a constant stroke.

Here, the material of the sheet guide 13 is arbitrary, and may be formed of synthetic resin or metal.

The elastic body 14 may be made of rubber or a soft synthetic resin in addition to the spring shown in the figure.

Also in the above embodiment, the cardboard A is pressed by the sheet guide 13 until the cutting edge 6a of the knife 6 starts to contact the cardboard A and completes the cutting.
It is possible to prevent the corrugated cardboard A from being bent and wrinkled, and it is possible to prevent the cut edge from being inclined.

Since a sheet guide 13 made of a hard material can be used, the cardboard A
It is possible to suppress wear due to contact with the metal and improve durability.

FIG. 3 shows a third embodiment of the rotary cutter according to the present invention. In this embodiment, an elastic body 14 made of a spring of the second embodiment shown in FIG.
Instead, an air tube filled with compressed air is used as the elastic body 14, and the elastic body 14 moves the sheet guide 13 outward by a predetermined stroke and presses it.

As described above, when an air tube is used as the elastic body 14, if the sheet guide 13 is long in the longitudinal direction of the knife rotor 1, the contact pressure between the sheet guide 13 and the cardboard A is reduced by the total length of the sheet guide 13. The cardboard A can be prevented from being crushed.

When the compressed air can be supplied to the elastic body 14 composed of the air tube,
Can be adjusted, and the pressing force with which the sheet guide 13 presses the cardboard A can be adjusted.
For this reason, even if the cardboard A is changed from thick to thin, or conversely, from thin to thick, various cardboards A having different thicknesses can be sheeted by adjusting the internal pressure of the air tube according to the thickness of the cardboard A. The pressing can be performed uniformly by the guide 13, and the crushing of the cardboard A can be prevented.

Also in the third embodiment, since a sheet guide 13 made of a hard material can be used, abrasion due to contact with the cardboard A can be suppressed, and the durability can be improved.

In the rotary cutter according to both the second and third embodiments, the protruding stroke of the sheet guide 13 and the elastic member which do not cause the corrugated cardboard A to be crushed at the time of cutting and do not cause folds. Fourteen elastic forces may be selected.

[0050]

As described above, according to the present invention, the knife is brought into contact with the cardboard because the sheet holder is provided at least on the leading side in the rotating direction of the knife to prevent the cardboard from being lifted by the sheet holder. It is possible to prevent the corrugated cardboard from being bent and creased from the abutment position until the cutting is completed, and to prevent the cut edge from being inclined, and to obtain a corrugated cardboard sheet having a good appearance and a high commercial value. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a rotary cutter according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the rotary cutter according to the present invention;

FIG. 3 is a sectional view showing a rotary cutter according to a third embodiment of the present invention;

FIG. 4 is a front view showing a conventional rotary cutter.

FIG. 5 is a perspective view showing the knife rotor according to the first embodiment;

FIGS. 6 (I), (II), and (III) are diagrams showing stepwise the cutting state of the corrugated cardboard by the rotary cutter of the above.
V) shows the cutting state of the cardboard

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Knife rotor 2 Anvil rotor 6 Knife 6a Blade tip 7a Sheet presser 13 Sheet guide 13a Sheet presser surface 14 Elastic body

Claims (6)

[Claims] A knife rotor and an anvil rotor opposed to the knife rotor are rotated in opposite directions to each other, and the blade edge of the knife extending in the longitudinal direction of the outer periphery of the knife rotor comes into contact with the outer periphery of the anvil rotor, thereby causing the both ends to rotate. A rotary cutter for cutting a corrugated board transferred between rotors in a width direction, wherein a sheet press for preventing the corrugated board from being lifted is provided at least on a leading side in a rotating direction of the knife. 2. The rotary cutter according to claim 1, wherein the sheet retainer is made of an elastic body. 3. The apparatus according to claim 2, wherein the sheet presser comprises a sheet guide supported slidably in the outer diameter direction of the knife rotor for a predetermined stroke, and an elastic body for pressing the sheet guide in the outer diameter direction of the knife rotor. Claim 1
The rotary cutter according to 1. 4. The rotary cutter according to claim 3, wherein said elastic body comprises a spring. 5. The rotary cutter according to claim 3, wherein said elastic body comprises an air tube in which compressed air is sealed. 6. The rotary cutter according to claim 5, wherein the internal pressure of the air tube is adjustable.