Cutter for cutting

Abstract

To provide a cutter for cutting which can inhibit flapping of a fed cardboard sheet (a sheet material) caused by contact with the cutter for cutting when a slit is made.SOLUTION: A cutter for cutting is used to form a slit in a sheet material and includes a cutter body which is formed in a fan shape and has grooving blades respectively provided at both side edges in a thickness direction along its outer periphery part. In an area which is a side surface area of the cutter body which contacts with a side surface of the slit formed by the grooving blade and excludes a blade edge part of the grooving blade, through holes which penetrate through the cutter body in the thickness direction are formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cutting tool, and particularly to a cutting tool for cutting sheet materials such as cardboard sheets.

Background Art

[0002] As a packaging box for storing or moving objects, etc., a cardboard box manufactured by assembling a cardboard sheet 100 as shown in FIG. 18 is known. The upper lid and the bottom plate of this cardboard box are formed by folding the portions separated by forming slits 101 in a part of the cardboard sheet 100 so as to overlap each other.

[0003] When forming this slit 101, a grooving device is generally used, and for this grooving device, a cutting tool 60 for cutting as shown in FIG. 19 is often used (for example, refer to the prior art of Patent Document 1).

[0004] This cutting tool 60 has a cutting edge generating blade 62 and a grooving blade 63 integrally formed on a blade body portion 61 formed in a fan shape. The cutting edge generating blade 62 protrudes radially outward from one end of the outer peripheral surface of the blade body 61 so as to be flush with the end surface of the blade body 61, and has corner portions 64 on both sides in the width direction of the end surface. The grooving blade 63 is provided on both sides in the thickness direction of the blade body 61 along the outer peripheral surface of the blade body portion 61.

[0005] The cutting tool 60 for cutting is attached to a grooving device 70 as shown in FIGS. 20 and 21. FIG. 20 is a side view showing a schematic configuration of the grooving device, and FIG. 21 is a front view. In this grooving device 70, two of the above-described cutting tools 60 for cutting are attached as upper blades. Regarding the configuration of the grooving device 70, each blade will be described below as cutting tools 60a and 60b for cutting.

[0006] The grooving device 70 includes an upper rotating shaft 71 and a lower rotating shaft 72. The upper rotating shaft 71 and the lower rotating shaft 72 are arranged parallel to each other and facing each other across the sheet feeding line L, and each is provided with a pair of disk-shaped upper rotating holders 73, 73 and a pair of lower rotating holders 74, 74.

[0007] Two cutting tools 60a, 60b, which are upper blades, are respectively clamped by fastening tools (not shown) such as bolts on the pair of upper rotating holders 73, 73. These cutting tools 60a, 60b are attached at a predetermined interval along the outer periphery of the pair of rotating holders 73, 73, and their respective cut generating blades 62a, 62b are attached so as to face each other along the outer peripheral direction. On the other hand, two receiving blades 75, 75, which are lower blades, are attached to the respective opposing surfaces of the pair of lower rotating holders 74, 74 with a predetermined interval set slightly wider than the thickness dimension of the cutting tools 60a and 60b. The receiving blades 75, 75 are ring-shaped cutting tools, and a blade portion is formed on the outer peripheral portion thereof. The ring-shaped receiving blades 75, 75 may be configured as receiving blades using a single ring-shaped cutting tool, or, for example, two cutting tools formed in a semi-ring shape may be installed on the lower rotating holders 74, 74 to form a ring-shaped receiving blade. Also, a ring-shaped receiving blade may be configured by installing a plurality of cutting tools formed in a fan shape on the lower rotating holders 74, 74.

[0008] Next, a method of forming a slit in a corrugated cardboard sheet 100 (sheet material) using the grooving device 70 having the above configuration will be described. As shown in FIG. 20, with the upper rotating holders 73, 73 and the lower rotating holders 74, 74 rotating at high speed, the corrugated cardboard sheet 100 is fed from the right side of FIG. 20 to the grooving device 70 along the sheet feeding line L of the grooving device 70. As a result, the cutting tool 60a, which is the upper blade, is sandwiched between the gaps of the receiving blades 75, 75, which are the lower blades, and the corrugated cardboard sheet 100 is cut, and a front slit 101 with the end portion 102 as shown in FIG. 18 as the end point is formed. Similarly, the other cutting tool 60b is sandwiched between the gaps of the receiving blades 75, 75, and the corrugated cardboard sheet 100 is cut, and a rear slit 101 starting from the start portion 103 is formed.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] However, when performing slit processing using a conventionally used cutting tool, the corrugated cardboard sheet 100 (sheet material) fed along the sheet feeding line L greatly fluctuates (vibrates) due to contact with the cutting tool, resulting in a problem that the noise during slit processing becomes large, and the impact during cutting received by the cutting tool becomes large, making the grooving blade 63 and the cut generation blade 62 prone to breakage.

[0011] The following will explain, with reference to FIGS. 22(a) to (d) showing the process of cutting a cardboard sheet 100 with a cutting tool for cutting, the reason why the cardboard sheet 100 fed along the sheet feeding line L sways due to contact with the cutting tool. First, FIG. 22(a) shows the state just before the cardboard sheet 100 is sandwiched between the cutting tool 62a (62b) which is the upper blade and the receiving blade 75 (cutting tool) which is the lower blade. From this state, as shown in FIG. 22(b), the cutting tool 62a (62b) which is the upper blade presses the cardboard sheet 100 from above and crushes it between the receiving blades 75, 75 which are the lower blades. Then, as shown in FIGS. 22(c) and (d), the cutting tool 62a (62b) which is the upper blade further presses and crushes the cardboard sheet 100 from above. The liner 100a of the cardboard sheet 100 is cut by the cutting tool 62a (62b) which is the upper blade, and the liner 100b of the cardboard sheet 100 is cut by the receiving blade 75 which is the lower blade.

[0012] Here, as shown in FIGS. 22(b) and (c), when the cutting tool 62a (62b) for cutting presses down the corrugated cardboard sheet 100 from above, the upper liner 100a of the corrugated cardboard sheet 100 is pulled in a direction approaching the outer surface of the cutting tool 62a (62b), and cutting proceeds in this state. That is, the end face (side face) 101a of the slit 101 in the upper liner 100a forms a slit while being in a state of relatively strongly contacting the outer surface of the cutting tool 62a (62b). Further, since the cutting tool 62a (62b) enters from the upper side to the lower side of the corrugated cardboard sheet 100 and then exits from the lower side to the upper side of the corrugated cardboard sheet 100, when entering from the upper side to the lower side of the corrugated cardboard sheet 100, as shown in FIG. 23(a), the end face (side face) 101a of the slit 101 in the upper liner 100a contacts the cutting tool 62a (62b) in a state facing downward following the movement of the cutting tool 62a (62b). On the other hand, when exiting from the lower side to the upper side of the corrugated cardboard sheet 100, as shown in FIG. 23(b), the end face (side face) 101a of the slit 101 in the upper liner 100a contacts the cutting tool 62a (62b) in a state facing upward following the movement of the cutting tool 62a (62b). Thus, due to the change in the behavior of the end face (side face) 101a of the slit when contacting the outer surface of the cutting tool 62a (62b) that rotates at high speed, it is considered that the fed corrugated cardboard sheet 100 will flutter.

[0013] The present invention has been made to solve such problems, and an object of the present invention is to provide a cutting tool that can suppress the fed corrugated cardboard sheet (sheet material) from fluttering due to contact with the cutting tool during slit processing.

Means for Solving the Problems

[0014] The object of the present invention is a cutting tool for forming a slit in a sheet material, which is formed in a fan shape and includes a tool body having grooving blades provided on both side edges in the thickness direction along its outer peripheral portion, and in a side surface region of the tool body that contacts the side surface of the slit formed by the grooving blade, in a region excluding the cutting edge portion of the grooving blade, a through hole penetrating in the thickness direction of the tool body is formed, which is achieved by a cutting tool characterized by this.

[0015] Further, in the above cutting tool, it is preferable that a plurality of the through holes are formed along the circumferential direction of the tool body.

[0016] Also, it is preferable that each of the through holes is formed at equal intervals along the circumferential direction of the tool body.

[0017] Further, the through hole may be configured as a strip-shaped through hole having the circumferential direction of the tool body as its longitudinal direction.

[0018] Also, the shape of the opening edge of the through hole is preferably formed in a fan shape, and an arc portion of the fan-shaped opening edge is arranged on the cutting edge side of the grooving blade, and a central portion of the fan is arranged on the radial center side of the tool body.

[0019] Also, it is preferable that a chamfered portion is formed on the opening edge of the through hole.

[0020] Also, the shortest distance between the inner peripheral edge of the through hole and the cutting edge of the grooving blade is preferably smaller than the thickness dimension of the sheet material in which the slit is formed.

[0021] Also, the width of the through hole along the radial direction of the tool body is preferably larger than the thickness dimension of the sheet material in which the slit is formed.

[0022] Further, the object of the present invention is a cutting tool for forming a slit in a sheet material, which is formed in a fan shape and includes a tool body having grooving blades provided on both side edges in the thickness direction along its outer peripheral portion. In a side surface region of the tool body that contacts a side surface of the slit formed by the grooving blade, in a region excluding the cutting edge portion of the grooving blade, a recess that is recessed in the thickness direction of the tool body is formed. The object is achieved by a cutting tool characterized by this.

[0023] In the above cutting tool, it is preferable that the recess is formed in a band shape along the circumferential direction of the tool body.

[0024] Further, it is preferable that a chamfered portion is formed at an opening edge of the recess.

[0025] Further, it is preferable that the shortest distance between the inner peripheral edge of the recess and the cutting edge of the grooving blade is smaller than the thickness dimension of the sheet material in which the slit is formed.

[0026] Further, it is preferable that the width of the recess along the radial direction of the tool body is larger than the thickness dimension of the sheet material in which the slit is formed.

[0027] Further, it is preferable that each grooving blade includes an outer surface flush with the side surface of the tool body and an inclined surface that inclines from the cutting edge toward the central portion side in the thickness direction of the tool body.

[0028] Further, it is preferable that a cut generation blade for forming an end portion of the slit is provided on one end side of the tool body.

[0029] Further, it is preferable that the cut generation blade is configured to be detachably attachable to one end side of the tool body.

[0030] Further, it is preferable that the cut generation blade includes a flat cutting edge portion.

[0031] Further, it is preferable that the cut generating blade has a semi-cylindrical blade tip portion.

[0032] Also, it is preferable that the cut generating blade has a blade tip notch at the tip of the blade tip portion.

[0033] Further, it is preferable that the width of the cut generating blade is substantially the same as the thickness of the tool body.

Advantages of the Invention

[0034] According to the present invention, it is possible to provide a cutting tool that can suppress the wobbling of a fed cardboard sheet (sheet material) due to contact with the cutting tool during slit processing.

Brief Description of the Drawings

[0035]

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Best Mode for Carrying Out the Invention

[0036] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that each figure is partially enlarged or reduced to facilitate understanding of the configuration. FIG. 1 is a plan view showing a cutting tool for cutting according to an embodiment of the present invention, and FIG. 2 is an enlarged view of the A-A cross section thereof. The cutting tool 1 for cutting is a tool for forming a slit in a sheet material such as a corrugated cardboard sheet or a synthetic resin sheet while rotating. As shown in FIGS. 1 and 2, it includes a tool body 2 and a cut generating blade 3.

[0037] The tool body 2 is formed of a metal material such as stainless steel, iron, or tool steel, and is formed in a fan shape in plan view as shown in FIG. 1. This tool body 2 is provided with two bolt holes 21 on one end side (one side surface side of the tool body 2). The bolt holes 21 are holes for attaching the cut generating blade 3 to the tool body 2 with bolts 50. It should be noted that the two bolt holes 21 are formed side by side along the radial direction of the tool body 2.

[0038] The cutting tool body 2 has grooving blades 22 provided on both side edges in the thickness direction along its outer peripheral portion. This grooving blade 22 is a blade portion configured to perform slitting on a sheet material, and includes an outer surface flush with the side surface of the cutting tool body 2 and an inclined surface inclined from the blade tip 22a toward the central portion side in the thickness direction of the cutting tool body 2. The specific form of this grooving blade 22 is not particularly limited. For example, as shown in the enlarged plan view of the main part of FIG. 3, it may be formed in a sawtooth shape. When the grooving blade 22 is formed in a sawtooth shape, the distance S between the apexes 221a of adjacent saw teeth 221 is formed to be, for example, 2.0 mm to 4.0 mm, and the maximum height H of each saw tooth 221 is formed to be, for example, 2.0 mm to 3.5 mm. Further, when the grooving blade 22 is formed in a sawtooth shape, as shown in FIG. 3, the contour shape 221b of the saw teeth 221 intervening between the apexes 221a of each saw tooth 3 may be formed to be V-shaped in plan view. As shown in FIG. 4(a), the contour shape 221b may be formed to be curved in plan view. Further, as shown in FIG. 4(b), the contour shape 221b may be formed to be V-shaped inclined to one side in plan view.

[0039] The cut generating blade 3 is a blade part for cutting off one end of the chip (slit chip) that comes out when the cutting tool 1 for cutting is slit processed from a sheet material such as a cardboard sheet to form the end of the slit. As shown in FIGS. 1 and 5(a) to (d), this cut generating blade 3 includes a flat plate-shaped attachment portion 31 detachably attached to one end side of the tool body 2, and a cutting edge portion 32 formed at one end portion of the attachment portion 31. The cutting edge portion 32 is configured such that its cutting edge is a flat edge. The thickness of the attachment portion 31 is set, for example, in the range of 2 mm to 15 mm. Here, FIG. 5(a) is a plan view when the cut generating blade 3 is viewed from above, FIG. 5(b) is a side view when viewed from the direction of arrow B in FIG. 5(a), FIG. 5(c) is a front view when viewed from the direction of arrow C in FIG. 5(a), and FIG. 5(d) is a rear view when viewed from the direction of arrow D in FIG. 5(a). The cut generating blade 3 is fixed to one end side of the tool body 2 such that the cutting edge portion 32 protrudes radially outward from the outer peripheral surface of the tool body 2, as shown in FIG. 1 for example. It is preferable that the width of this cut generating blade 3 is configured to be substantially the same dimension as the thickness of the tool body 2. Further, the attachment portion 31 is configured to be long in the direction along the radial direction of the tool body 2, and includes a through hole 33 formed corresponding to the bolt hole 21 formed in the tool body 2. In the present embodiment, the contour of the attachment portion is configured to be rectangular in plan view. The cut generating blade 3 is fixed to a predetermined position of the tool body 2 by tightening the bolt 50 and pressing the attachment portion 31 against the tool body 2 side with the bolt head. The portion around the through hole 33 becomes the portion that abuts against the bolt head of the bolt 50.

[0040] In the cut generating blade 3 in FIG. 5, the through hole 33 is formed in an elongated hole shape along the radial direction of the tool body 2, and the attachment portion 31 (cut generating blade 3) is configured such that the cutting edge portion 32 can be adjusted in position in the radial direction of the tool body 2. That is, the dimension in the longitudinal direction of the elongated hole-shaped through hole 33 is configured to be longer than the distance between the two bolt holes 21 formed in the tool body 2 (the distance between the bolt holes 21 including the two bolt holes 21). The width dimension of this through hole 33 (the width dimension in the vertical direction in FIG. 5(a)) is set to be larger than the diameter of the shaft portion of the inserted bolt 50.

[0041] In the above-described embodiment, as the cut generation blade 3 that cuts off one end of the chip pieces that come out when being slit by the cutting tool 1 for cutting, a structure that is detachably attached to one end side of the tool body 2 is provided. However, the structure is not particularly limited to this. For example, as shown in FIG. 19 shown in the conventional example, it can also be formed integrally with the tool body 2 and protrude radially outward from one end of the outer peripheral surface of the tool body 2 so as to be flush with the end surface of the tool body 2.

[0042] In the present invention, as shown in FIGS. 1 and 2, during the slitting process, in the side surface region of the tool body 2 that contacts the side surface (cut end surface) of the slit formed by the grooving blade 22, excluding the tip portion of the grooving blade 22, a through hole 4 penetrating in the thickness direction of the tool body 2 is formed. The through hole 4 is formed by performing laser processing or the like on the tool body. Further, as shown in FIG. 1, it is preferable that a plurality of through holes 4 are formed along the circumferential direction of the tool body 2. Further, when forming a plurality of through holes 4, it is preferable that they are formed at equal intervals along the circumferential direction of the tool body 2. Further, the shortest distance between the inner peripheral edge of the through hole 4 and the cutting edge 22a of the grooving blade 22 is preferably configured to be smaller than the thickness dimension of the sheet material in which the slit is formed. Further, the width of the through hole 4 along the radial direction of the tool body 2 is preferably configured to be larger than the thickness dimension of the sheet material in which the slit is formed. Further, it is preferable that the opening edge of the through hole 4 is chamfered. Note that the shape of the through hole 4 (the shape of the opening) is not particularly limited, and it can be configured in various shapes such as a circular shape, a square shape, and an elliptical shape in a plan view. Further, as shown in the plan view of FIG. 6, the through hole 4 may be configured as a strip-shaped through hole having the circumferential direction of the tool body 2 as the longitudinal direction. Further, as shown in the plan view of FIG. 1, instead of forming the through holes 4 dispersed over the entire circumferential direction of the tool body 2, as shown in the plan view of FIG. 7, they may be formed only in a predetermined area in the circumferential direction of the tool body 2. Further, as shown in the cross-sectional view of FIG. 2, the through hole 4 may be configured such that a part of the through hole 4 penetrates the grooving blade 22, or, as shown in the cross-sectional view of FIG. 8, the through hole 4 may be formed in the grooving blade 22 provided in the tool body 2. Further, as shown in the cross-sectional view of FIG. 9, the through hole 4 may be formed in the region excluding the grooving blade 22.

[0043] The cutting tool 1 having the above configuration is attached to and used in a grooving device 70 (cutting device) as shown in FIGS. 20 and 21, for example. Since the method of forming a slit in a sheet material such as a cardboard sheet is the same as the method described in the above background art, a detailed description thereof is omitted here.

[0044] The cutting tool 1 according to this embodiment is a side surface region of the tool body 2 that contacts the end surface (side surface) of the slit formed by the grooving blade 22, and in the region excluding the cutting edge portion of the grooving blade 22, it is provided with a through hole 4 penetrating in the thickness direction of the tool body 2. Therefore, as shown in the explanatory drawing of FIG. 10, when entering from the upper side to the lower side of the corrugated cardboard sheet 100 to form a slit, or when passing through from the lower side to the upper side of the corrugated cardboard sheet 100, the area of the side surface region of the tool body 2 that contacts the end surface (side surface) 101a of the formed slit can be reduced. As a result, it becomes possible to make the change in the behavior of the end surface (side surface) 101a of the slit when the end surface (side surface) 101a of the slit in the upper liner 100a of the corrugated cardboard sheet contacts the outer surface of the cutting tool 1 rotating at high speed small, and it is possible to suppress the corrugated cardboard sheet 100 to be fed from fluttering. As a result, it is possible to suppress the noise during slit processing from becoming large. Furthermore, the impact during cutting received by the cutting tool 1 is reduced, and the effect that the grooving blade 63 and the cut generation blade 62 are less likely to be damaged is exhibited. Also, since a chamfered portion is formed at the opening edge of the through hole 4, when the side surface (cutting end surface) of the slit of the corrugated cardboard sheet 100 contacts the peripheral portion of the through hole 4, it is effectively prevented that the cutting end surface of the slit is caught by the through hole 4, and it becomes possible to more effectively exhibit the above effects.

[0045] As described above, the cutting tool 1 according to an embodiment of the present invention has been explained. However, the specific configuration of the cutting tool 1 is not limited to the above embodiment. In the above embodiment, the cutting edge portion 32 of the cut generation blade 3 is configured as a flat blade. However, for example, as shown in FIG. 11, it may be configured in a semi-cylindrical form, and one end portion on the back surface side thereof may be notched as shown by the broken lines in FIGS. 11(a) and 11(b), so that a semi-circular cutting edge is formed on one end outer peripheral edge. Note that the cut generation blade 3 is attached to one end side of the tool body 2 in a direction in which the outer peripheral curved surface of the cutting edge portion 32 is exposed to the one end side of the tool body 2. Here, FIG. 11(a) is a plan view when the cut generation blade 3 is viewed from above, FIG. 11(b) is a side view when viewed from the direction of arrow E shown in FIG. 11(a), FIG. 11(c) is a front view when viewed from the direction of arrow F shown in FIG. 11(a), and FIG. 11(d) is a rear view when viewed from the direction of arrow G shown in FIG. 11(a).

[0046] Also, in the above embodiment, the cut generation blade 3 is formed in a flat plate shape and is configured to include a cutting edge portion 32 as a flat blade at one end portion. However, as shown in FIG. 12(a), one or a plurality of cutting edge notch portions 321 may be formed in the cutting edge portion 32. Further, even when the cut generation blade 3 is configured in a semi-cylindrical form as shown in FIG. 11 and a semi-circular cutting edge is formed on one end outer peripheral edge thereof, one or a plurality of cutting edge notch portions 321 may be formed in the cutting edge (the tip of the cutting edge portion 32) as shown in FIG. 12(b).

[0047] Also, in the above embodiment, the configuration of the cut generation blade 3 that is fixed to the tool body 2 by two bolts 50 while the cutting edge portion 32 of the cut generation blade 3 is configured to be position-adjustable in the radial direction of the tool body 2 has been explained. However, it is not particularly limited to such a configuration, and a configuration may be adopted in which the cut generation blade 3 is fixed to the tool body 2 by a single bolt 50 so as to be position-adjustable in the radial direction of the tool body 2.

[0048] In addition, in the above-described embodiment, the cutting tool body 2 is configured to have a fan-shaped form. However, for example, as shown in FIG. 13, a main body notch portion is formed by cutting out one end side of the cutting tool body 2 in a substantially triangular shape in a plan view, and a support surface 27 having an inclination of an angle θ with respect to the end surface 25 of the cutting tool body 2 may be provided. The angle θ is preferably in the range of 5° to 30°, particularly preferably in the range of 10° to 20°, and is set to 15° in this embodiment. The bolt hole 21 used when fixing the cut generation blade 3 is formed in the support surface 27, and the cut generation blade 3 is attached to the support surface 27.

[0049] In addition, in the above-described embodiment, as shown in the plan view of FIG. 1, the through hole 4 is configured such that the opening edge shape is circular. However, for example, as shown in the enlarged plan view of the main part of FIG. 14, it may be configured as a through hole 4 having a fan-shaped opening edge shape. It is preferable that the arc portion of the fan-shaped opening edge shape is disposed on the cutting edge 22a side of the groove cutting blade 22, and the central portion of the fan is disposed on the radial center side of the cutting tool body 2. By adopting the through hole 4 in such a form, it becomes possible to more effectively exhibit the above-described effects.

[0050] In addition, in the above-described embodiment, as shown in FIG. 2, the groove cutting blade 22 having a V-shaped cross section is provided. However, it is not particularly limited to such a configuration. For example, as shown in the enlarged schematic cross-sectional view of the main part of FIG. 15, the outer peripheral surface of the groove cutting blade 22 may be configured as a flat curved surface, and the corner portions on both sides in the thickness direction of the cutting tool body 2 may be configured as the cutting edges 22a.

[0051] In addition, in the above-described embodiment, during the slitting process, a configuration has been described in which a through hole 4 penetrating in the thickness direction of the tool body 2 is formed in a side surface region of the tool body 2 that contacts the side surface (cut end surface) of the slit formed by the groove cutting blade 22, excluding the tip portion of the groove cutting blade 22. However, even with a configuration other than such a through hole configuration, the above-described effects can be obtained. Specifically, as shown in the plan view of FIG. 16 and the cross-sectional view of FIG. 17, instead of forming the through hole 4, the tool body 2 may be configured to include a recess 5 on its side surface. The depth dimension of the recess 5 is not particularly limited, but for example, it is preferably 1.5 mm or more and 3.5 mm or less, and more preferably 2 mm or more and 3 mm or less. Further, the recess 5 can be formed, for example, by end mill machining. Needless to say, this recess 5 is formed in a side surface region of the tool body 2 that contacts the side surface (cut end surface) of the slit formed by the groove cutting blade 22, excluding the tip portion of the groove cutting blade 22, during the slitting process.

[0052] As shown in FIG. 16, this recess 5 is preferably formed in a strip shape along the circumferential direction of the tool body 2. Further, it is preferable that a chamfered portion is formed at the opening edge of the recess 5. Further, the shortest distance between the inner peripheral edge of the recess 5 and the tip of the groove cutting blade 22 is preferably smaller than the thickness dimension of the sheet material in which the slit is formed. Further, the width of the recess 5 along the radial direction of the tool body 2 is preferably configured to be larger than the thickness dimension of the sheet material in which the slit is formed. By configuring to include the recess 5 instead of the through hole 4 in this way, the strength of the tool body 2 can be improved.

Explanation of Reference Numerals

[0053] 1 Cutting tool 2 Tool body 22 Groove cutting blade 3 Notch generating blade 4 Through hole 5 Recess

Claims

1. A cutting tool for forming slits in a sheet material, comprising: a tool body formed in a fan shape and having grooving blades provided on both side edges in the thickness direction along its outer peripheral portion; a side surface region of the tool body that contacts the side surface of the slit formed by the grooving blade, and in a region excluding the cutting edge portion of the grooving blade, a through hole penetrating in the thickness direction of the tool body is formed. The cutting tool is characterized by this.

2. The cutting tool according to claim 1, wherein a plurality of the through holes are formed along the circumferential direction of the tool body.

3. The cutting tool according to claim 2, wherein each of the through holes is formed at equal intervals along the circumferential direction of the tool body.

4. The cutting tool according to claim 1 or 2, wherein the through hole is a strip-shaped through hole having the circumferential direction of the tool body as its longitudinal direction.

5. The cutting tool according to claim 1 or 2, wherein the shape of the opening edge of the through hole is formed in a fan shape, an arc portion of the fan-shaped opening edge is disposed on the cutting edge side of the grooving blade, and a central portion of the fan is disposed on the radial center side of the tool body.

6. The cutting tool according to claim 1 or 2, wherein a chamfered portion is formed on the opening edge of the through hole.

7. The cutting tool according to claim 1 or 2, wherein the shortest distance between the inner peripheral edge of the through hole and the cutting edge of the grooving blade is smaller than the thickness dimension of the sheet material in which the slit is formed.

8. The cutting tool according to claim 1 or 2, wherein the width of the through hole along the radial direction of the tool body is larger than the thickness dimension of the sheet material in which the slit is formed.

9. A cutting tool for forming slits in a sheet material, comprising: a tool body formed in a fan shape and having grooving blades provided on both side edges in the thickness direction along its outer peripheral portion; a side surface region of the tool body that contacts the side surface of the slit formed by the grooving blade, and in a region excluding the cutting edge portion of the grooving blade, a recess recessed in the thickness direction of the tool body is formed. The cutting tool is characterized by this.

10. The cutting tool according to claim 9, wherein the recess is formed in a strip shape along the circumferential direction of the tool body.

11. The cutting tool according to claim 9 or 10, wherein a chamfered portion is formed at the opening edge of the concave portion.

12. The cutting tool according to claim 9 or 10, wherein the shortest distance between the inner peripheral edge of the concave portion and the cutting edge of the grooving blade is smaller than the thickness dimension of the sheet material in which the slit is formed.

13. The cutting tool according to claim 9 or 10, wherein the width of the concave portion along the radial direction of the tool body is larger than the thickness dimension of the sheet material in which the slit is formed.

14. Each of the grooving blades according to claim 1 or 9, wherein the grooving blade includes an outer surface flush with the side surface of the tool body and an inclined surface inclined from the cutting edge toward the central portion side in the thickness direction of the tool body.

15. The cutting tool according to claim 1 or 9, wherein a cut generation blade for forming an end portion of the slit is provided on one end side of the tool body.

16. The cutting tool according to claim 15, wherein the cut generation blade is configured to be detachably attached to one end side of the tool body.

17. The cutting tool according to claim 15, wherein the cut generation blade includes a cutting edge portion with a flat blade.

18. The cutting tool according to claim 15, wherein the cut generation blade includes a cutting edge portion with a semi-cylindrical shape.

19. The cutting tool according to claim 15, wherein the cut generation blade has a cutting edge notch at the tip of the cutting edge portion.

20. The cutting tool according to claim 15, wherein the width of the cut generation blade is substantially the same as the thickness of the tool body.

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