JPH06143023A - Slitting of sheet material and slitter device - Google Patents

Abstract

PURPOSE:To omit adjustment of clearance between an upper cutter and a lower cutter, and to improve efficiency of recombination work of the upper and lower cutters. CONSTITUTION:A disc-shape upper cutter 1 on which edges are formed along both side ends, is bitten into a lower cutter 4 on which a groove 4a of a width to which a clearance required for the thickness of the upper cutter 1, and a sheet material 12 is inserted between them, and a chip 9 of the length corresponding to the width of the upper cutter is cut. Since a clearance is determined when the thickness of the upper cutter 1 and the groove width of the lower cutter 4 are determined, adjustment of the clearance is not required even when the width of a slit is to be changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for slitting a sheet material and a slitter device used for the method. More specifically, the invention relates to a method of slitting a sheet-shaped or strip-shaped metal plate or the like (hereinafter referred to as a sheet material) between a pair of round blades and a slitter device used for the method. The term "slitting" is a concept that includes not only the case where the sheet material is slit in the longitudinal direction with a constant width to form the hoop material, but also the so-called trimming processing in which both sides of the sheet material are cut off and aligned straight. .

[0002]

2. Description of the Related Art Generally, when a sheet material is slit into a certain width, a pair of upper and lower shafts (arbors) arranged laterally with respect to the traveling direction of the sheet material are used to support round blades. Insert the sheet material between the round blades so that it can be pinched. At that time, the sheet material is pulled toward the exit side to rotate the round blades, or either one or both round blades are rotationally driven. in this case,
As shown in FIG. 10, the edges 103 and 104 of the pair of round blades 101 and 102 overlap each other with an axial clearance C therebetween. The overlap amount at this time is V in FIG. In order to perform such a slit method, round blades (knives) and spacers are alternately inserted into the upper and lower arbor 106 to set the slitting width, and at the same time, the clearance C between the upper and lower round blades 101 and 102 is set.
Adjust. Then, adjust the distance between the upper and lower arbors to adjust the amount of overlap. When the sheet material is slit by such a slitting method, a burr shown by 107 in FIG. 10 occurs. Although the clearance amount C is conventionally set to about 1/10 of the thickness t of the normal sheet material 105,
It has long been required to reduce the amount of burr 107 as much as possible. Therefore, when the thickness of the sheet material is thin (for example, 0.05 to 0.1 mm), the clearance amount C becomes extremely small, which makes adjustment difficult. In particular, when slitting in multiple lines, it is extremely difficult to adjust the intervals between all adjacent round blades. In order to solve such a problem, the present applicant has already filed JP-A-2-232115 and JP-A3-1.
A slitter device described in Japanese Patent No. 96912 is proposed. In these devices, each arbor is provided with an individual arbor, and the height and axial position of the arbor can be adjusted independently of other round blades, facilitating adjustment of clearance and overlap. There is. However, although these devices allow adjustment for each pair of round blades to facilitate the adjustment work, the adjustment work itself is indispensable. Further, in the device disclosed in Japanese Patent Laid-Open No. 2-232115, clearance adjustment is automated, but since a mechanism for automation is assembled, the distance between adjacent round blades becomes large, and a narrow slit cannot be formed. There is. On the other hand, as a device that facilitates the fixing of the round blade to the arbor, a hydraulic expansion / contraction arbor (arbor having a structure in which the outer diameter of the arbor is expanded / contracted by hydraulic pressure to fix the round blade), or an expandable / contractible spacer, a half spacer, etc. Has been advocated from early on. However, in the conventional slit method of sandwiching a sheet material with a pair of round blades, a thrust force (F in FIG. 10) acts to separate the round blades from each other in the axial direction. Therefore, in order to appropriately maintain the clearance C against the lateral force F, the round blades 101, 1
It is necessary to fix 02 to the arbor 106 with an extremely large fixing force. It is also necessary to maintain the clearance C with high accuracy. Therefore, it is difficult to practically use the circular blade fixing with the hydraulic expansion / contraction arbor. In addition, the expandable spacer and the half spacer also have a larger number of parts than normal spacers, so manufacturing errors accumulate during assembly,
When the sheet material is thin, it is difficult to use in practice.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the need to adjust the clearance between the upper and lower round blades, to improve the efficiency of the round blade reassembling work, and to make the round blade easy to arbor. An object of the present invention is to propose a slit method and device that can be attached, can maintain a clearance with high accuracy, and have a small burr.

[0004]

In order to solve the above problems, the slitting method of the present invention uses a disk-shaped first circular blade having a constant blade thickness and having edges formed along both side edges. The second round blade, which is supported by the first shaft and has a groove having a width obtained by adding a clearance required for the thickness of the first round blade to the outer circumference, is formed by the second shaft parallel to the first shaft. While supporting and allowing the peripheral edge of the first round blade to be bitten into the groove of the second round blade with a predetermined overlap amount, while rotating both round blades in the opposite direction, the sheet material is passed between them to form the groove. The feature is that the sheet material is slit while being cut in. Furthermore, the slitter device of the present invention has a disk-shaped first round blade having a constant blade thickness and having edges formed along both side edges, supported by a first shaft, and the outer periphery of the first round blade is A second round blade formed with a groove having a width obtained by adding a necessary clearance to the blade thickness is supported by a second shaft parallel to the first shaft, and the first round blade is provided in the groove of the second round blade. It is characterized in that the peripheral edge portion of is engaged with a predetermined overlap amount. In such a slitter device, a waste removing member having a guide surface having a portion submerged in the groove of the second round blade and a portion smoothly connected to this portion and extending to the outside of the groove is provided. Is preferred. Further, it is preferable that the first round blade has a thin disc shape, the first round blade is sandwiched from both sides, and is coupled to the first shaft through a pair of holders. Furthermore, the first round blade can be replaced. It is preferable that the first shaft is sandwiched between the first shaft and the first shaft. It is preferable that a plurality of pairs of the first round blade and the second round blade are provided, and at least one of the first shaft and the second shaft is an independent arbor provided independently for each round blade. It is preferable to prepare a plurality of first round blades so that they can be freely combined with one set of second round blades, because the slit width can be more easily adjusted. By providing a drive mechanism for moving the set of the first round blade and the second round blade together in the axial direction of the shaft, the utility value of the present invention is further enhanced.

[0005]

In the method and apparatus of the present invention, as shown in FIG. 2, the first round blade 1 is inserted into the groove 4a of the second round blade 4 (lower blade).
Since the peripheral edge portion 1a of the (upper blade) is engaged, the gaps between the both side surfaces of the first round blade 1 and the inner side surface of the groove 4a of the second round blade are clearances C1 and C2. The value (C1 + C2) including the clearances on both sides does not change during slit processing. Further, the sheet material 12 is slit by the edges 1b, 1c on both side edges of the first round blade 1 and the edges 4b, 4c on the upper end of the inner side surface of the groove 4a of the second round blade 4, so that the scrap 9 with a narrow width is removed. It becomes scrap and is symmetrically slit on both edges of the narrow width scrap 9 under substantially the same conditions. Therefore, the clearances C1 and C2 on both sides of the first round blade 1 are automatically equalized. Therefore, since the addition of the clearances on both sides (C1 + C2) does not change, the left and right clearances C1 and C2 also do not change during slit processing. After all, the sheet material 12 to be slit
Once the blade thickness T of the first round blade and the groove width W of the second round blade are selected according to the thickness of the clearance, the clearance is fixed, and the combination of the first and second round blades is determined. Even if it is set to the position, there is no need to adjust the clearance.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method and apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an essential part showing an embodiment of the slitting method of the present invention. In FIG. 1, reference numeral 1 denotes a disc-shaped round blade (hereinafter referred to as an upper blade) attached to the upper arbor 3a, which is the first round blade of claim 1. Further, 4 is a round blade (hereinafter referred to as a lower blade) attached to the lower arbor 3b, which is the second blade of claim 1. Between the upper blade 1 and the lower blade 4, the sheet material 12 is advanced in the horizontal direction (direction of arrow S). The upper blade 1 is the lower arbor 3b.
In addition, the lower blade 4 may be attached to the upper arbor 3a, and in principle, the inclination or the traveling direction of the sheet material 12 may be any direction. The upper blade 1 is sandwiched by holders 2 from both sides, and is provided on the upper arbor 3a so as to be movable in the axial direction. A groove 4a having a width (W in FIG. 2) somewhat larger than the blade thickness (T in FIG. 2) of the upper blade 1 is formed on the outer circumference of the lower blade 4, and the peripheral portion of the upper blade 1 is formed in the groove 4a. 1a is inserted. Therefore, the sheet material 12 traveling in the direction of arrow S is
A scrap 9 having a width corresponding to the width W of the groove 4a is cut into the groove 4a, so that the left and right slits are separated. Hereinafter, each element used in this method will be described.

<Structure of Upper Blade> As shown in FIG. 2, the upper blade 1 is in the form of a thin disk, and has edges 1b,
1c is formed. Further, since the upper blade 1 is thin and has low rigidity strength, as shown in FIG. 3, the upper blade 1 is sandwiched by a pair of holders 2a, 2b having a diameter smaller than the outer diameter of the upper blade 1, and integrated to increase the rigidity strength, and then the upper arbor 3a. It has a structure that binds to.
That is, a disk-shaped convex portion 2c is provided on one of the pair of holders 2a and 2b, and a concave portion 2d that fits the convex portion 2c is provided on the other 2b. Then, a hole for fitting the convex portion 2c is formed in the central portion of the upper blade 1, the hole is fitted into the convex portion 2c of the one holder 2a, and then the hole is fitted between the holders 2a and 2b by the bolt 21a. It is sandwiched. When slitting with the combination of the upper blade 1 and the groove 4a of the lower blade 4, the groove 4 of the lower blade 4
The sheet material is cut off with a width corresponding to the width W of a. Therefore, especially in the case of a multi-row slit, the yield becomes low. To reduce the decrease in yield, the upper blade 1
In the case where the sheet material is steel, the appropriate limit thickness of the blade is around the thickness of the sheet material in terms of strength of the slit portion of the blade. For example, when slitting steel having a plate thickness of 0.3 mm, the blade thickness of the upper blade is 0.3 mm. However, in the actual state, the upper blade having a blade thickness of 0.3 mm is warped. Since this warp is generated when the load of the grinding and polishing is removed during the grinding and polishing of the side surface of the upper blade, the accuracy of the blade thickness itself is good. Therefore, if the upper blade is sandwiched by the holders 2a and 2b as shown in FIG. 3, such warpage can be corrected, and at the same time, the rigidity strength of the blade can be increased. The material of the upper blade is not particularly limited, but a material such as cemented carbide having high strength and high wear resistance is preferable. Thereby, the thickness of the upper blade can be reduced, and the yield can be increased. The inventors of the present invention have found that the material of the upper blade: SKH, the blade thickness: 0.5 mm, the material of the lower blade: SKD, the material of the sheet material: mild steel, the plate thickness: 0.
As a result of a slitting test performed at 1 to 0.4 mm, it was confirmed that the service lives of the upper and lower blades were longer than before.

<Structure of Lower Blade> The lower blade 4 shown in FIG. 4 (a) is formed by forming a groove 4a on the outer peripheral surface of one thin disk-shaped material. The width W of the groove 4a is the thickness T of the upper blade 1 plus the required clearances C1 and C2. The depth of the groove 4a is not particularly limited as long as it does not hinder the removal of waste. In the case of the lower blade 4, the upper end corners of the inner surface of the groove 4a cooperate with the edge of the upper blade 1 to form the edges 4b and 4c for slitting the sheet material. As a method of providing the groove 4a in the lower blade 4, as shown in FIG. 4 (a), the groove 4a is formed by cutting in one plate material, and as shown in FIG. 4 (b), two disk shapes are formed. It is also possible to sandwich the spacer 7 having a smaller diameter than the blade members 4d and 4e. In this way, by changing the thickness of the spacer 7, the groove 4a
There is an advantage that the width of can be freely changed. Further, there is an advantage that both sides of the blade member can be used by utilizing the edges on both sides of each blade member 4d, 4e. As in the case of FIG. 2, FIG. 4c shows the two blade members 4d and 4e and the spacer 7 unitized by a pair of holders 8. In this way, when changing the slit width, the entire unit can be moved on the arbor 3, so that the work of exchanging the blade becomes easy. This is particularly advantageous when automatically setting the slit width as described later.

<Scrap Removal Member> When the upper blade 1 and the lower blade 4 are combined as shown in FIG. 1 and the sheet material 12 is slit in the direction of arrow S between them, the groove 4 is formed as shown in FIG.
The narrow width scrap 9 (scrap) enters into a. Therefore, if slit processing is performed to some extent, it is necessary to take out the scraps. Further, the scrap 9 has entered the groove 4a quite hard. 5 (a) and 5 (b) show such a scrap 9
1 shows a waste removing member for continuously and automatically taking out the waste. The scrap removing member shown in FIG. 5A is composed of a scrap removing blade 10 extending in the tangential direction of the lower blade 4 and having its tip inserted into the groove 4 a of the lower blade 4. The upper surface of the scrap removal blade 10 is sunk into the groove 4a on the tip side, and is located outside the groove 4a on the base end side. Therefore, the scrap 9 is guided by the upper surface of the scrap discharging blade 10 and is sequentially drawn to the outside as the lower blade 4 rotates. 5A has a base end side attached to a stationary member, so that the upper blade 1 and the lower blade 4 are combined along the axial direction of the arbor 3 in order to change the slit width. When moving it, it is necessary to have a structure that allows it to move. Therefore, the supporting member of the scrap removal blade 10 is the lower blade 4
The mounting structure can be changed in the axial direction according to the position of. The scrap removing member of FIG. 5B is a scrap discharging ring 1 fitted in the groove 4a of the lower blade 4 and on the outer periphery of the spacer 7 with play.
It is composed of 1. That is, the scrap removal ring 11 has an inner diameter slightly larger than the outer diameter of the spacer 7. The outer peripheral surface of the waste discharging ring 11 is sunk into the groove 4a on the upper side thereof, and the outer peripheral surface protrudes from the groove 4a on the side or the lower side. Therefore, the scraps 9 are continuously discharged to the outside along the outer peripheral surface of the scrap discharging ring 11. Even when the scraper ring 11 moves the set of the upper blade 1 and the lower blade 4 along the axial direction of the lower arbor 3b to change the slit width,
It is convenient because it can be moved together with the lower blade 4.

<Incorporation into conventional slitter device> FIG. 6 is a sectional view of the lower blade shown in FIG. 4 (b) incorporated into a conventional slitter device. The slitter device includes a base 22, left and right housings 23 and 24 standing up from both sides of the base 22, and an upper arbor 3a and a lower arbor 3b rotatably supported by the housings via bearings. In this embodiment, a long axis arbor (common arbor) is used as the arbor. The upper arbor 3a is provided with the upper blade 1 shown in FIG. The interval between the both end surfaces of the upper blades 1, 1 becomes the slit width. The upper blade 1 is not fixed to the upper arbor 3a, but can move in the axial direction to some extent. That is, by engaging the upper blade 1 with the groove 4a of the lower blade 4,
Its axial position is only fixed. A fixed flange 25 is attached to the left end of the lower arbor 3b, and a ring-shaped flange 26 is fastened with a nut 27 to the right end. Then, between the fixed flange 25 and the ring-shaped flange 26, the lower blades 4 are attached with a plurality of spacers 5 spaced apart from each other. In addition, 6 is a rubber sleeve and 11 is a ring for removing dust. The position of the lower blade 4 is determined only by the spacer 5 and the flanges 25 and 26. Furthermore, lower blade 4
In the two blade members 4d and 4e and the spacer 7 between them, the position of each lower blade 4, the distance between the lower blades, and the groove width are maintained by the axial tightening force of the nut 27. In the slitter device assembled in this way, the clearance is fixed because the upper blade 1 is in the groove of the lower blade 4, and it is not necessary to adjust the clearance any further. Further, since the left and right clearances are the same due to the balance of the left and right forces when slitting the sheet material, it is not necessary to fix the upper blade 1 to the upper arbor 3a. Further, it is preferable not to fix them, because the left and right clearances are automatically made the same. In the slitter device configured as described above, slight surface runout (deviation in the axial direction) of the upper blade 1 and the lower blade 4 is allowed. FIG. 7 shows FIG.
It is sectional drawing at the time of incorporating the lower blade 4 of c in the conventional slitter device, and other parts are the same as the slitter device of FIG. In this case, the force generated when the sheet material is slit becomes the internal stress, so that the force for fixing the lower blade 4 to the lower arbor 3b can be reduced. That is, when slitting, an outward reaction force is applied to the two blade members 4d and 4e,
Since this reaction force is balanced by the tension of the bolt 21b, it does not become an external force to the arbor 3b.
In the slitter device of FIGS. 6 and 7, the accuracy of the fixed position of the lower blade does not affect the clearance. It only affects the accuracy of the slit width. Therefore, the positioning accuracy can be reduced from the conventional clearance accuracy of the upper and lower blades to the product width accuracy.

<When the upper blade is incorporated in an independent arbor>
8a and b, the upper blade 1 is provided with an independent arbor 2
8a is a front view and a side view in a case where the upper arbor 28a is assembled into the upper frame 29a and is axially slidably attached to the upper frame 29 so as to be slidable in the axial direction and vertically adjustable. That is, a tool rest 30 is slidably attached to the upper frame 29, and with respect to the clevis 31 of the tool rest 30,
An arbor 28a is rotatably attached to the tip of an arm 33 rotatably provided by a pin 32. The arm 33
The rotation angle of can be adjusted with the screw 34 attached to the clevis 31, and thereby the height of the upper blade 1 can be adjusted. Therefore, when the outer diameter of the upper blade 1 is reduced to a smaller diameter, this can be compensated for each upper blade, and the overlap amount can be adjusted. Further, when the number of slits is smaller than the number of pairs of the upper blade 1 and the lower blade 4 which are incorporated in advance, the arm 33 may be released upward to float the upper blade 1, and the upper and lower blades are removed one by one. There is no need for trouble. Further, the upper blades 1 can be replaced independently. In case of independent arbor, each upper arbor 28
Since a can be shortened, a small diameter is sufficient, and therefore the upper blade 1 itself can be made small in diameter. Therefore, the accuracy of the blade can be improved, the cost can be reduced, and the handling can be facilitated. Further, by appropriately selecting the length of the arm 33 in FIG. 8, the swing amount of the arm can be increased. Therefore, when replacing the upper blade 1, the lower blade 4 can be easily replaced and adjusted without being disturbed. Also, the imaginary line R1 in FIG.
As shown by, the rubber wheel 35 can be incorporated into the upper blade not using the slit, and the sheet material 12 can be pinched on the rubber sleeve 6 on the lower arbor. By doing so, it is possible to prevent the sheet material 12 from trying to rise between the adjacent upper blades 1, and there is an advantage that a smooth feed can be ensured. In the embodiment shown in FIG. 8, the upper arbor 28a is not driven, but the sheet material 12 is pulled from the exit side so that the upper blade is driven to rotate and cut off as the sheet material runs. In this case, it is not necessary to drive the lower blade side either. However, it is also possible to connect a motor or the like to the upper and lower arbors 3a and 3b and perform slitting while rotating the upper blade 1 or the lower blade 4. Further, as described above, when the sheet material 12 is pinched by the upper and lower rubber wheels 35, only the lower blade is rotationally driven and the upper blade 1
It is also possible to make the slit free and make a slit while rotating it.

<When Upper and Lower Blades are Incorporated into Independent Arbors> FIG. 9 shows an embodiment in which the upper blade 1 and the lower blade 4 are incorporated into independent arbors 28a and 28b. In this way, the replacement work of the lower blade 4 can be facilitated and the diameter thereof can be reduced. If the upper blade 1 can be moved up and down, it is not necessary to move the lower blade 4 up and down. Therefore, the tool post 37 for the lower blade is simply slid in the axial direction and fixed at that position,
The width can be set, and it is not necessary to remove the lower blade 4 from the tool rest 37 even when changing the size of the material.

<When the upper and lower blades are automatically adjusted to the slit width> As shown by an imaginary line R2 in FIG. 9, the tool rest 30 of the upper blade 1 or the tool rest 37 of the lower blade 4 is provided with a screw member such as a ball screw. When the screw member is screwed (not shown) and the screw member is accurately rotated by a servomotor or the like, the axial position of the upper blade 1 or the lower blade 4 can be set by numerical data or the like. If a ball screw is provided on the tool post of the lower blade, the slit width can be automatically adjusted.
In the present invention, since the adjustment of the clearance is unnecessary as described above, the positional accuracy when fixing the respective tool rests is sufficient with the accuracy of the slit width. Therefore, the slit width automatic adjusting mechanism can be realized relatively easily.

[0014]

In the conventional slitter device, it is difficult to adjust the clearance and fix the blade, so that special skill is required for setting the blade. With the method and apparatus of the present invention, anyone can easily slit a sheet material having an arbitrary width without requiring such special skill. Furthermore,
Since clearance can be adjusted easily with high reliability, adjustment time can be shortened, slit quality can be improved, abnormal wear of round blades can be reduced, and equipment availability can be improved. In addition, the amount of movement of the round blade unit can be quantified, so that the amount can be stored in a computer, enabling a fully automated slitter system. Further details have the following advantages. (1) No clearance adjustment is required for changing blades during operation. (2) The clearance can be set with high accuracy, can be maintained with high accuracy, and good sharpness can be maintained for a long time. (3) Since a gap corresponding to the blade thickness of the upper blade is formed between the sheet materials after slitting, there is no problem that the end surfaces of the sheet materials touch and overlap each other. (4) The accuracy and fixing force for fixing the lower blade to the arbor can be reduced. (5) Since the upper blade is constrained in the groove of the lower blade, axial fixing is not necessary. Further, by making the mechanism capable of positively sliding in the axial direction, the surface wobbling of the blade can be absorbed. (6) From the above (4) and (5), the method of fixing the blade such as the hydraulic expansion / contraction arbor, the expanding / contracting spacer, or the half spacer can be easily used. (7) Since a large force is not required to fix the blade and the accuracy of fixing the blade can be reduced from the clearance accuracy to the slit width accuracy, the blade positioning can be easily automated.

[Brief description of drawings]

FIG. 1 is a perspective view showing a position embodiment of a slitting method of the present invention.

FIG. 2 is a sectional view of an essential part showing an embodiment of the slitter device of the present invention.

FIG. 3 is a cross-sectional view showing an embodiment of an upper blade and a holder according to the present invention.

4 (a) to 4 (c) are cross-sectional views showing an embodiment of a lower blade according to the present invention.

FIG. 5 (a) and FIG. 5 (b) are side views showing an embodiment of a debris removing mechanism according to the present invention.

FIG. 6 is a partial sectional view showing the entire other embodiment of the slitter device of the present invention.

FIG. 7 is a partial sectional view showing the whole of still another embodiment of the slitter device of the present invention.

FIG. 8 is a partial schematic view showing the whole of still another embodiment of the slitter device of the present invention, FIG. 8 (a) is a front view thereof, and FIG. 8 (b) is a side view thereof.

FIG. 9 is a front view showing still another embodiment of the slitter device of the present invention.

FIG. 10 is a cross-sectional view of essential parts showing an example of a conventional slitter device.

[Explanation of symbols]

 1: Upper blade 2: Holder (for fixing upper blade) 3: Arbor 4: Lower blade 5: Spacer (for setting width) 6: Rubber sleeve 7: Spacer (for setting clearance) 8: Holder (for fixing lower blade) 9 : Scrap 10: Scrap discharging blade 11: Scrap discharging ring 12: Sheet material

Claims (10)

[Claims] 1. A disk-shaped first round blade having a constant blade thickness and having edges formed along both side edges is supported by a first shaft, and the outer periphery has a blade thickness of the first round blade. A second round blade having a groove having a width with a necessary clearance added thereto is supported by a second shaft parallel to the first shaft, and a groove of the second round blade has a peripheral edge of the first round blade. The sheet material is characterized in that the portion is bitten with a predetermined overlap amount, and while rotating both round blades in opposite directions, the sheet material is passed between them and the sheet material is slit while being cut into the groove. Slit method. 2. A disk-shaped first round blade having a constant blade thickness and having edges formed along both side edges is supported by a first shaft, and has a blade thickness of the first round blade on the outer periphery. A second round blade having a groove having a width added with a necessary clearance is supported by a second shaft parallel to the first shaft, and a peripheral portion of the first round blade is provided in the groove of the second round blade. A slitter device that bites a certain amount of overlap. 3. A debris removing member having a portion that is submerged in the groove of the second round blade and a portion that is integrally connected to this portion and that extends to the outside of the groove. Equipment. 4. The device according to claim 3, wherein the debris removing member is constituted by a ring loosely fitted in the groove of the second round blade. 5. The apparatus according to claim 2, wherein the second round blade is composed of two blade members having the same diameter and a spacer sandwiched between the blade members. 6. The second round blade has a thin disc shape, and both sides of the first round blade are sandwiched by a pair of holders having a diameter slightly smaller than that of the first round blade. Equipment. 7. A plurality of sets of the first round blade and the second round blade are provided, and at least one of the first shaft and the second shaft is independently provided for each round blade. The device of claim 2 which is a separate arbor. 8. The apparatus according to claim 6, wherein a plurality of first round blades are provided so as to be freely combined with one set of second round blades. 9. The apparatus according to claim 6, wherein the first round blade is replaceably held by a holder. 10. A set of the first round blade and the second round blade,
The device according to claim 2, further comprising a drive mechanism for moving the shaft together with the drive shaft.