JP2002273689A - Sheet cutting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tape cutting device having blade edges whose wear is suppressed, involving less risk of damage of the blade edges such as cracking or chipping, and equipped with an upper blade and a lower blade having a long lifetime. SOLUTION: The upper blade 18 and lower blade 14 of this sheet cutting device 10 are formed as rotating disc, and the peripheries of the disc surfaces serve as cutting edges 40 and 38 arranged so that the blade edges are contacting with each other, and a magnetic sheet 20 to intrude continuously in the direction parallel with the disc surfaces of the upper 18 and lower blades 14 is cut by the edges 40 and 38 of the blades 18 and 14 rotating in the opposite direction to each other. In lieu of an upper blade 18 and lower blade 14 whose cutting edges contact with each other as in the conventional arrangement, the upper 18 and lower blades 14 of this sheet cutting device 10 are chamfered so that their edges 40 and 38 do not contact with each other when the blades 18 and 14 rotate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet cutting apparatus for cutting a sheet to produce a tape having a predetermined width, and more particularly, to a blade such as abrasion, crack, chipping or the like on the upper and lower blades. The present invention relates to a sheet cutting device having a configuration that does not cause partial loss.

[0002]

2. Description of the Related Art Magnetic tapes such as audio tapes and video tapes are produced by subjecting a wide magnetic sheet (raw sheet) manufactured through predetermined steps such as a calendering step and a curing step to a plurality of strips using a sheet cutting device. It is manufactured by cutting.

Referring to FIG. 5, the structure of a conventional sheet cutting apparatus will be described. FIG. 5 is a perspective view showing an example of a conventional sheet cutting apparatus. As shown in FIG. 5, the sheet cutting device 10 includes a plurality of lower blades 14 held at predetermined intervals in an axial direction of the first shaft 12 and an axial direction of a second shaft 16 parallel to the first shaft 12. And a plurality of upper blades 18 held at predetermined intervals. The upper blade 18 and the lower blade 14 are each formed as a rotatable disk body, and a peripheral portion of the disk surface is a blade portion. The second shaft 16 is located at a position away from the first shaft 12 during standby before the cutting operation, and separates the upper blade 18 from the lower blade 14. The blade portions of the lower blade 14 and the upper blade 18 that come close to each other and make a pair overlap each other by a predetermined amount.

At the time of cutting, the magnetic sheet 20 holds the upper blade 1
8 and continuously enter in a direction parallel to the disk surface of the lower blade 14,
The upper blade 18 and the lower blade 14, which rotate in the counterclockwise and clockwise directions, respectively, are cut to a predetermined width. The rotation speeds of the lower blade 14 and the upper blade 18 are set corresponding to the traveling speed of the magnetic sheet 20, respectively. After being cut, the magnetic sheet 20 becomes the magnetic tapes 22 and 24 and runs separately in different directions. Magnetic tape 22 directed downward
The running direction is changed by the guide roller 28 and is wound around the hub 32 to form a pancake. On the other hand, the magnetic tape 24 running above, like the magnetic tape 22,
It is wound into another hub (not shown) to form a pancake.

The width of each of the magnetic tapes 22 and 24 is, for example,
1/8 inch for audio system, 1/2 for VHS system
It is set to inches, and further to 8 mm for so-called 8 mm video systems. In this manner, the magnetic tapes 22 and 24 cut to a predetermined width are assembled into corresponding cassettes and commercialized.

The lower blade 14 and the upper blade 18 of the sheet cutting device 10
Are shown in FIGS. 6 and 7. Figure 6 shows the lower blade 1
7 shows an example in which the disk surface of the upper blade 18 paired with the lower blade 4 is formed in a plane, and FIG. 7 shows an example in which the disk surface of the upper blade 18 paired with the lower blade 14 is formed in a dish shape. In both figures, the other configurations are the same except that the disk surface of the upper blade 18 is different. As shown in FIGS. 6 and 7, holders 34 respectively holding the upper blades 18 are fixed to the second shaft 16 at predetermined intervals in the axial direction. The upper blade 18 coaxially mounted on each holder 34 is the upper blade 18 and the holder 3 respectively.
4 is urged by a disc spring 36 fitted to a step 34a between the holders 34 so as to be separated from the holder 34 in the axial direction.

In the sheet cutting apparatus, when cutting the sheet,
First, in a state where both the upper blade 18 and the lower blade 14 do not rotate,
The second shaft 16 is moved closer to the first shaft 12. Then, the blade portion 40 of the upper blade 18 is overlapped with the corresponding blade portion 38 of the lower blade 14 by a predetermined amount. At this time, the blade portion 40 and the blade portion 38 are not in contact with each other. Next, the second shaft 16 is shifted by a predetermined distance, for example, about 100 μm in a direction of an arrow a parallel to the first shaft 12,
The blade portion 38 which makes the blade portion 40 a pair by the elastic force of the disc spring 36
The upper blade 18 and the lower blade 14 are rotated in a state where the magnetic sheet 20 is brought into contact with the magnetic sheet 20 and cut.

[0008]

However, in the above-described sheet cutting device, the blades of the upper blade and the lower blade are significantly worn, and the blades are cracked or chipped. There was a problem that the service life of the lower blade was short. In the above description, cutting of a magnetic sheet has been described as an example, but such a sheet cutting apparatus is widely used not only for cutting a magnetic tape but also for cutting various sheets other than a magnetic tape. Therefore, the problem that the service life of the upper blade and the lower blade is short is a problem applicable to the sheet cutting apparatus in general.

Accordingly, an object of the present invention is to provide a tape cutting device provided with an upper blade and a lower blade which have a long service life, in which wear of the blade portion is suppressed, occurrence of cracks and chipping and the like in the blade portion is reduced. That is.

[0010]

The inventor of the present invention has investigated the causes of the occurrence of the above-mentioned edge defects such as wear, cracks and chipping, and has paid attention to the following points. First, the blade 3
The wear of the blades 8 and 40 is remarkable, and the cracks and chipping (blank chipping) of the blades 38 and 40 are caused by the blades 38 and 40.
The cause is that the 40s come into contact with each other. As below,
The contact between the blade portions 38 and 40 can be described.

When the upper blade 18 shown in FIG. 6 is brought close to the lower blade 14, the upper blade 18 is urged by the disc spring 36, and the blade 40 is pressed against the blade 38. Due to the reaction force of the blade portion 38 with respect to the blade portion 40, the upper blade 18 slightly rotates counterclockwise and inclines against the urging force of the disc spring 36. As a result, the upper blade 18 and the lower blade 14 make one point contact with the upper end of the disk surface of the lower blade 14 at the intermediate point P1 of the blade portion 40 of the upper blade 18 as shown in FIG. Thereby, the magnetic sheet 20
The blade portion 40 and the blade portion 38 only overlap, and enter the cutting portion 42 that is not actually in contact, and is cut there. That is, the upper blade 18 and the lower blade 14 shown in FIG. 6 satisfactorily cut the magnetic sheet that continuously enters even though the blade portion 40 is not actually in contact with the blade portion 38.

On the other hand, the upper blade 18 shown in FIG.
4, the upper blade 18 and the lower blade 1 shown in FIG.
Like FIG. 4, although the upper blade 18 is slightly rotated counterclockwise and inclined against the urging force of the disc spring 36, the upper blade 18 is formed in a dish shape, so that it is shown in FIG. So, blade part 3
8 and the blade portion 40 make two-point contact at points P2 and P3. As a result, the magnetic sheet 2 traveling in the direction of arrow A as in FIG.
0 is the cutting portion 4 where the upper blade 18 and the lower blade 14 actually contact.
2 and is cut at the cutting section 42 that has come into contact with the cutting section.

In view of the above, the inventor of the present invention has assumed that in the case of FIG. 6, even if the blade portions of both the upper blade 18 and the lower blade 14 in FIG. Inferred no effect. In addition, in the upper blade 18 and the lower blade 14 shown in FIG. 7, even if the blade portions do not contact each other at the contact point P <b> 2 where the sheet is cut, the upper blade 18 and the lower blade 14 in FIG. Thought that the sheet could be cut effectively. The inventor has confirmed these through experiments, and has come to invent the present invention.

In order to achieve the above object, based on the above-mentioned knowledge, the sheet cutting apparatus according to the present invention has:
An upper blade that is formed as a rotatable disk body and has a pair of upper blades and lower blades arranged so that the periphery of the disk surface is a blade portion and the blade portions are in contact with each other, and rotates in opposite directions to each other. In the sheet cutting device configured to cut a sheet that continuously enters in a direction parallel to the disk surfaces of the upper blade and the lower blade, the blade portion of the lower blade replaces the upper blade and the lower blade where the blade portions contact each other. The upper and lower blades are chamfered so that the blade portions do not come into contact with each other when the upper and lower blades rotate.

The sheet cutting apparatus of the present invention includes the upper blade and the lower blade which are chamfered so that the blade portions do not come into contact with each other at the time of cutting, instead of the upper blade and the lower blade which are in contact with each other. When cutting the sheet, the paired upper blade and lower blade do not actually come into contact with each other. Thereby, it is possible to reliably prevent the occurrence of wear or chipping of the blade portion of the upper blade and the lower blade during sheet cutting, thereby extending the service life of the upper blade and the lower blade. ,
The cut shape of the magnetic tape can be made good.

In a preferred sheet cutting apparatus of the present invention, the blade portions of the upper blade and the lower blade are chamfered so as to form mutually parallel inclined surfaces. In this case, the chamfered surface can be easily manufactured by a simple polishing process.

Further, a preferable mode is one in which the blade portions of the upper blade and the lower blade are chamfered so as to have concave curved surfaces facing each other. In this case, the blade portions of the upper blade and the lower blade are chamfered so that the angle between the concave curved surface provided on the blade portion of the upper blade and the lower blade and the outer peripheral surface of the upper blade and the lower blade is 90 degrees or less. Then, the cutting function by the upper blade and the lower blade can be further enhanced.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment 1 This embodiment is an example of an embodiment of a sheet cutting apparatus according to the present invention, and FIG. 1 is a cross-sectional view of a lower blade and an upper blade showing a configuration of a blade portion of this embodiment. . The sheet cutting apparatus according to the present embodiment has the same configuration as that of FIG.
9 has the same configuration as the sheet cutting apparatus 10 described with reference to FIG. In the sheet cutting device of the present embodiment, the blade 4
As shown in FIG. 1, instead of the conventional upper blade 18 and lower blade 14 in contact with each other, the upper blade 18 and the lower blade 14 are chamfered so that the blade portions 40 and 38 do not contact each other when the upper blade 18 and the lower blade 14 rotate. The upper blade 18 and the lower blade 14 are provided. That is, the blade portions 40 and 38 of the upper blade 18 and the lower blade 14 are chamfered so that the mutually facing blade portions become inclined surfaces 44 and 46 that are parallel to each other. These inclined surfaces 44, 46
Can be formed relatively easily by polishing.

In the lower blade 14, the blade portion 38 is formed so that the angle A formed between the inclined surface 44 and the outer peripheral surface 45 of the lower blade 14 is obtuse.
Is chamfered. Further, the upper blade 18 also has an inclined surface 46.
The blade portion 40 is chamfered so that an angle B formed between the blade portion 40 and the outer peripheral surface 47 of the upper blade 18 becomes an obtuse angle. Blades 38 and 40
Are respectively parallel to each other, and preferably, the angles A and B are respectively
It is in the range of 91 ° to 110 °.

FIG. 2 is a cross-sectional view showing the positional relationship between the lower blade and the upper blade provided in the tape cutting device of this embodiment, with the magnetic sheet 20 interposed therebetween. At the time of cutting, the upper blade 18
The magnetic sheet 20 is moved from the state before the movement shown in FIG. 2A to the cutting position shown in FIG. When cutting the sheet, even if the upper blade 18 and the lower blade 14 rotate,
Since the blade portions 40 and 38 of the upper blade 18 and the lower blade 14 have the inclined surfaces 44 and 46, respectively, the blade portions do not contact each other. The magnetic sheet 20 to be cut in this embodiment is formed by depositing a magnetic coating film 20b on a base film 20a made of a plastic film.

That is, in this embodiment, the inclined surface 46,
44, the magnetic sheet 20 continuously entering in a direction parallel to the disk surfaces of the upper blade 18 and the lower blade 14
Cutting can be performed smoothly in a state where the blade portions 40 and 38 of the upper blade 18 and the lower blade 14 do not contact each other. As a result, the cutting edge of the upper blade 18 and the lower blade 1 can be reduced by wear and chipping caused by cutting and the like caused during cutting of the magnetic sheet by the conventional sheet cutting device.
4 does not occur in each of the blade portions 40 and 38.

The sheet cutting device according to the present embodiment is, for example, three times as large as a magnetic sheet that could be cut only 200,000 m by the conventional sheet cutting device 10 without causing any breakage in the blade portions 40 and 38. It could be cut to 600,000 m. As described above, the sheet cutting apparatus according to the present invention can be expected to exert great power even on a tape which is difficult to cut such as a vapor-deposited tape which will be a mainstream of magnetic tapes in the future.

Embodiment 2 This embodiment is another example of the embodiment of the tape cutting apparatus according to the present invention. FIG. 3 shows a lower blade and an upper blade showing the configuration of a blade portion of this embodiment. FIG. The sheet cutting device according to the present embodiment is the same as the sheet cutting device according to the first embodiment except that the configuration of the blade portion is different. In the sheet cutting device according to the present embodiment, as shown in FIG.
And the blade portions 40 and 38 of the lower blade 14 are chamfered so as to form concave curved surfaces 50 and 48 facing each other, so that the blade portions 40 and 38 do not contact each other during rotation. Like the inclined surfaces 44 and 46 of the first embodiment, the concave curved surfaces 50 and 48 can be formed relatively easily by polishing.

In the lower blade 14, the blade 38 is chamfered so that the angle A between the concave curved surface 48 and the outer peripheral surface 45 of the lower blade 14 is 90 degrees or less. Also, in the upper blade 18, the angle B between the concave curved surface 50 and the outer peripheral surface 47 of the upper blade 18 is 90 °.
The blade portion 40 is chamfered so as to be equal to or less than a degree. Concave curved surface 48 and concave curved surface 5 provided on blade portions 38 and 40, respectively
0 preferably the angles A and B each range from 70 ° to 90 °.

FIG. 4 is a cross-sectional view showing the positional relationship between the lower blade and the upper blade provided in the tape cutting device of this embodiment, with the magnetic sheet 20 interposed therebetween. At the time of cutting, the upper blade 18
The magnetic sheet 20 is cut from the state before the movement shown in FIG. 4A to the cutting position shown in FIG. When cutting the sheet, even if the upper blade 18 and the lower blade 14 rotate,
Since the blade portions 40 and 38 of the upper blade 18 and the lower blade 14 have concave curved surfaces 48 and 50, respectively, the blade portions do not contact each other.

That is, in this embodiment, the concave curved surface 48,
With the provision of the blades 50, the magnetic sheet 20 continuously entering the blades 40, 38 of the upper blade 18 and the lower blade 14 can be moved.
Can be cut smoothly without contacting each other. As a result, blade defects such as abrasion and chipping generated during cutting of the magnetic sheet by the conventional sheet cutting device do not occur in the blade portions 40 and 38 of the upper blade 18 and the lower blade 14. Moreover, since the angles A and B of the concave curved surfaces 48 and 50 are set to 90 degrees or less, the cutting function of the upper blade 18 and the lower blade 14 is further enhanced, and a sharp tape cut can be obtained. it can.

[0027]

As described above, according to the present invention,
By providing an upper blade and a lower blade that are chamfered so that the blade portions do not contact each other when the upper blade and the lower blade rotate, instead of the upper blade and the lower blade that are in contact with each other, It is possible to obtain a tape cutting device provided with an upper blade and a lower blade, which suppresses abrasion, causes less occurrence of cracks and chippings in the blade portion, and has a long service life.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lower blade and an upper blade showing a blade configuration of a sheet cutting device according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views illustrating a positional relationship between a lower blade and an upper blade according to the first embodiment, where FIG. 2A illustrates a state before the upper blade is moved to a cutting position, and FIG. 2 shows a state after moving to the cutting position.

FIG. 3 is a sectional view of a lower blade and an upper blade showing a blade configuration of a sheet cutting device according to a second embodiment of the present invention.

4A and 4B are cross-sectional views illustrating a positional relationship between a lower blade and an upper blade according to a second embodiment. FIG. 4A illustrates a state before the upper blade is moved to a cutting position, and FIG. 2 shows a state after moving to the cutting position.

FIG. 5 is a perspective view showing an example of a conventional sheet cutting device.

6 is a sectional view showing details of a lower blade and an upper blade of the sheet cutting device shown in FIG. 5;

FIG. 7 is a sectional view of another example showing details of a lower blade and an upper blade of the sheet cutting device shown in FIG. 5;

FIG. 8 is a side view showing a positional relationship between an upper blade and a lower blade corresponding to FIG. 6 at the time of cutting a sheet.

9 is a side view showing a contact state of an upper blade and a lower blade corresponding to FIG. 7 at the time of cutting a sheet.

[Explanation of symbols]

10 Tape cutting device 12 First shaft 14
... lower blade, 16 ... second shaft, 18 ... upper blade, 20
...... magnetic sheet, 22, 24 ... magnetic tape, 34 ...
Holder, 36: Belleville spring, 38, 40 ... Blade, 42 ...
... Cutting section, 44, 46... Inclined surface, 45, 47... Outer peripheral surface, 48, 50.

Claims (4)

[Claims] 1. Each of the blades is formed as a rotatable disk body, and has a pair of upper blades and lower blades arranged so that the periphery of the disk surface is a blade portion and the blade portions are in contact with each other. In a sheet cutting device configured to cut a sheet that continuously enters in a direction parallel to the disk surfaces of the upper blade and the lower blade by the blade portions of the upper blade and the lower blade that rotate in the directions, the blade portions contact each other. A sheet cutting device comprising an upper blade and a lower blade which are chamfered so that the blade portions do not contact each other when the upper blade and the lower blade rotate, instead of the blade and the lower blade. 2. The sheet cutting device according to claim 1, wherein the blade portions of the upper blade and the lower blade are chamfered so as to have mutually parallel inclined surfaces. 3. The sheet cutting device according to claim 1, wherein the blade portions of the upper blade and the lower blade are chamfered so as to have concave curved surfaces facing each other. 4. The upper and lower blades are chamfered so that the angle between the concave surface provided on the upper and lower blades and the outer peripheral surface of the upper and lower blades is 90 degrees or less. The sheet cutting device according to claim 3, wherein the sheet cutting device is used.