Cutter for cutting processing

Abstract

To provide a cutter for cutting processing capable of preventing damage from occurring at a slit end part during slit processing.SOLUTION: Provided is a cutter for cutting processing comprising a cutter body for forming a slit and a notch generating blade 3 for forming an end part of the slit. The cutter body is formed in a fan shape and comprises grooving blades 22 provided on both side edges in a thickness direction along its outer periphery. The notch generating blade is configured to protrude, on one end side of the cutter body, radially outward from the cutter body, and a tip of the grooving blade comprises a first area E1 and a second area E2 along a circumferential direction. The first area is an area connected to the notch generating blade, and the second area is connected to the first area and extends from a connection position thereof to the other end of the cutter body. The second area is formed in an arc shape having the same radius, and the first area is formed as a recessed area that is recessed radially inside the cutter body from a virtual arc line that passes through the arc-shaped tip.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] As a packing box for storing or moving objects, etc., a cardboard box manufactured by assembling a cardboard sheet 100 as shown in FIG. 17 is known. The upper lid and the bottom plate of this cardboard box are formed by folding the parts 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. 18 is often used (see, for example, 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 part 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 parts 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 part 61.

[0005] The cutting tool 60 for cutting is attached to a grooving device 70 as shown in FIGS. 19 and 20. FIG. 19 is a side view showing a schematic configuration of the grooving device, and FIG. 20 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 groove cutting 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 with the sheet feeding line L interposed therebetween, 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 to the pair of upper rotating holders 73, 73 by fastening tools (not shown) such as bolts. 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 formed 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 cardboard sheet 100 (sheet material) using the grooving device 70 having the above configuration will be described. As shown in FIG. 19, with the upper rotating holders 73, 73 and the lower rotating holders 74, 74 rotating at high speed, the cardboard sheet 100 is fed from the right side of FIG. 19 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 cardboard sheet 100 is cut, forming a front slit 101 with the end portion 102 as shown in FIG. 17 as the end point. Similarly, the other cutting tool 60b is sandwiched between the gaps of the receiving blades 75, 75, and the cardboard sheet 100 is cut, forming a rear slit 101 starting from the starting end portion 103.

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 cutting tool that has been conventionally used, in the case of the front slit, there has been a problem that damage such as fraying at the slit end formed by the cut generation blade or peeling of the cardboard sheet skin occurs. Hereinafter, the causes of fraying damage and the like occurring at the slit end will be explained. First, when forming a slit with a cutting tool, as shown in FIGS. 21(a) and 21(b), the grooving blade 63 of the cutting tool 60 enters the cardboard sheet 100 in order from the side where the cut generation blade 62 is not formed as the cutting tool 60 rotates and cuts (FIG. 21(a)). Then, finally, when the cut generation blade 62 penetrates the cardboard sheet 100, the slit debris is separated from the cardboard sheet 100 and the slit is formed (FIG. 21(b)).

[0011] Here, the state just before the cut generation blade 62 penetrates the cardboard sheet is as shown in the enlarged view of the main part of FIG. 22, and the cut end surface of the cardboard sheet 100 during the slit processing in the state of FIG. 22 is as shown in FIG. 23. As shown in FIG. 23, just before the cut generation blade 62 penetrates the cardboard sheet 100, the separated slit scraps are still connected to the cardboard sheet 100, but the connection part Z1 that has not been cut on both sides of the cardboard sheet 100 is only in an extremely narrow area (or may not exist at all). When the cutting edge of the cut generation blade 62 penetrates the cardboard sheet 100, the separated slit scrap part is not stably held by the cardboard sheet 100. Thus, as a result of the separated slit scrap part not being stably held by the cardboard sheet 100, the biting state of the cutting edge of the cut generation blade 62 when it penetrates the cardboard sheet 100 deteriorates, smooth cutting by the cutting edge cannot be achieved, the skin (surface part) of the liner on the lower side of the cardboard sheet 100 peels off in a wide range due to the pressing by the cutting edge, or fraying occurs at the slit end.

[0012] The present invention has been made to solve such problems, and an object thereof is to provide a cutting tool for cutting that can prevent damage from occurring at the slit end when performing slit processing.

Means for Solving the Problems

[0013] The object of the present invention is a cutting tool for forming a slit in a sheet material, comprising a tool body for forming the slit and a cut generating blade for forming the end of the slit. The tool body is formed in a fan shape and is provided with groove cutting blades respectively provided on both side edges in the thickness direction along its outer peripheral portion. The cut generating blade is configured to project outward in the radial direction of the tool body at one end side of the tool body. The cutting edge of the groove cutting blade includes a first region and a second region along the circumferential direction. The first region is a region connected to the cut generating blade. The second region is a region connected to the first region and extending from the connection position to the other end of the tool body. The second region is formed in an arc shape having the same radius. The first region is formed as a concave region recessed inward in the radial direction of the tool body from a virtual arc line passing through the arc-shaped cutting edge. This is achieved by a cutting tool for cutting processing.

[0014] Further, in the above cutting tool, it is preferable that the concave region is formed in a curved shape having a concave vertex in a region between the connection position with the second region and the connection position with the cut generating blade.

[0015] Further, the concave region formed in the curved shape is preferably formed so as to smoothly incline from the connection position with the second region toward the concave vertex and smoothly incline from the concave vertex toward the connection position with the cut generating blade.

[0016] Further, it is preferable that the first region and the cutting edge of the cut generating blade are smoothly connected.

[0017] Further, the second region includes a third region connected to the first region. The third region is preferably formed as a convex region protruding outward in the radial direction of the tool body from a virtual arc line passing through the arc-shaped cutting edge.

[0018] Further, it is preferable that the convex portion region is formed in a curved shape having a convex portion apex in a region between the connection position with the first region and the connection position with the arc-shaped region of the second region.

[0019] Further, the convex portion region formed in the curved shape is preferably formed so as to smoothly incline from the connection position with the first region toward the convex portion apex and to smoothly incline toward the connection position with the arc-shaped region of the second region.

[0020] Further, it is preferable that the third region is disposed on one end side rather than at an intermediate position between one end and the other end of the blade body.

[0021] Further, it is preferable that the convex portion apex of the convex portion region is disposed on the inner side in the radial direction of the blade body rather than a cutting edge line passing through the cutting edge of the cutting edge generating blade, which is a virtual line parallel to the arc line.

[0022] Further, the third region includes a first inclined region extending from the connection position with the arc-shaped region of the second region toward the convex portion apex of the convex portion region and a second inclined region extending from the convex portion apex of the convex portion region toward the first region, and it is preferable that the inclination angle of the second inclined region is larger than the inclination angle of the first inclined region.

[0023] Further, it is preferable that each groove cutting blade includes an outer surface flush with the side surface of the blade body and an inclined surface inclined from the cutting edge toward the central portion side in the thickness direction of the blade body.

[0024] Further, it is preferable that the cutting edge generating blade is integrally formed with the blade body.

[0025] Further, it is preferable that the cutting edge generating blade is configured to be detachably attachable to one end side of the blade body.

[0026] Further, it is preferable that the cutting edge generating blade includes a flat cutting edge portion.

[0027] Further, it is preferable that the cut generation blade has a blade tip notch at the tip of the blade tip portion.

[0028] Also, it is preferable that the cut generation blade includes a semi-cylindrical blade tip portion.

[0029] Also, it is preferable that the width of the cut generation blade is substantially the same as the thickness of the blade body.

Advantages of the Invention

[0030] According to the present invention, it is possible to provide a cutting tool that can prevent damage from occurring at the slit end when performing slit processing.

Brief Description of the Drawings

[0031]

Figure 1

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Figure 17

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Figure 23

Embodiments for Carrying Out the Invention

[0032] Hereinafter, a first embodiment according to the present invention will be described with reference to the accompanying drawings. It should be noted that each figure is partially enlarged or reduced for easy understanding of the configuration. FIG. 1 is a plan view showing a cutting tool for cutting according to the first embodiment of the present invention, FIG. 2 is an enlarged view of the main part thereof, and FIG. 3 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 cardboard sheet or a synthetic resin sheet while rotating. As shown in FIGS. 1 to 3, it includes a tool body 2 and a cut generation blade 3.

[0033] The tool body 2 is formed of a metal material such as stainless steel, iron, or tool steel. As shown in FIG. 1, it is formed in a fan shape as a whole in plan view. The cut generation blade 3 is provided on one end side (one side surface side of the tool body 2) of the tool body 2.

[0034] The tool body 2 has grooving blades 22 provided on both side edges in the thickness direction along its outer peripheral portion. The grooving blade 22 is a blade portion configured to perform slit processing on a sheet material, and includes an outer surface flush with the side surface of the tool body 2 and an inclined surface inclined from the blade tip 22a toward the central portion side in the thickness direction of the tool body 2. The specific form of the grooving blade 22 is not particularly limited. For example, as shown in the enlarged plan view of the main part of FIG. 4, 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. When the grooving blade 22 is formed in a sawtooth shape, as shown in FIG. 4, 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, or as shown in FIG. 5(a), the contour shape 221b may be formed to be curved in plan view. Further, as shown in FIG. 5(b), the contour shape 221b may be formed to be V-shaped inclined to one side in plan view.

[0035] The cut generation blade 3 is a blade part for cutting off one end of a 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. The cut generation blade 3 is configured to project outward in the radial direction of the tool body 2 on one end side of the tool body 2. In this embodiment, the cut generation blade 3 is integrally formed with the tool body 2. Further, the cutting edge portion of the cut generation blade is configured as a flat blade, and the width of the cut generation blade 3 is configured to be substantially the same dimension as the thickness of the tool body 2.

[0036] In the present invention, as shown in FIGS. 1 and 2, the cutting edge of the groove cutting blade 22 is formed to include a first region E1 and a second region E2 along the circumferential direction. The first region E1 is a region connected to the cut generation blade 3, and the second region E2 is a region that connects to the first region E1 and extends from the connection position to the other end of the tool body 2. The second region E2 is formed in an arc shape having the same radius, and the first region E1 is formed as a concave region 225 that is recessed inward in the radial direction of the tool body 2 from a virtual arc line L1 that passes through the arc-shaped cutting edge. When the cutting edge of the groove cutting blade 22 is formed in a sawtooth shape, the first region E1 and the second region E2 are set with respect to the line connecting the respective vertices 221a of the sawteeth.

[0037] Further, the concave region 225, which is the first region E1, is formed in a curved shape having a concave vertex 225a in the region between the connection position with the second region E2 (the region formed in an arc shape) and the connection position with the cut generation blade 3. More specifically, the concave region 225 formed in a curved shape is smoothly inclined from the connection position with the second region E2 toward the concave vertex 225a, and is smoothly inclined from the concave vertex 225a toward the connection position with the cut generation blade 3. Further, as going from the connection position with the second region E2 toward the concave vertex 225a, the distance (depth) from the virtual arc line L1 to the cutting edge gradually increases, and as going from the concave vertex 225a toward the connection position with the cut generation blade 3, the distance (depth) from the virtual arc line L1 to the cutting edge is configured to gradually decrease. Also, the first region E1 (concave region 225) and the cutting edge of the cut generation blade 3 are configured to be smoothly connected.

[0038] Next, a second embodiment according to the present invention will be described with reference to the accompanying drawings. FIG. 6 is a plan view showing a cutting tool according to the second embodiment of the present invention, and FIG. 7 is an enlarged view of a main part thereof. The cutting tool 1 for cutting according to this second embodiment is configured such that the shape of the cutting edge of the groove cutting blade 22 is different from that of the cutting tool for cutting according to the first embodiment. The cutting edge of the groove cutting blade 22 in the cutting tool for cutting according to the second embodiment is formed to include a first region E1 and a second region E2 along the circumferential direction. The second region E2 includes an arc-shaped region E21 having the same radius and a third region E22 connected to the first region E1. Here, the first region E1 is a region connected to the cut generation blade 3, similar to the first embodiment described above, and is formed as a concave region 225 that is recessed radially inward of the tool body 2 with respect to a virtual arc line L1 passing through the arc-shaped cutting edge (arc-shaped region E21) in the second region E2. The first region E1 is configured to have the same structure as that of the first embodiment described above.

[0039] The third region E22 included in the second region E2 is formed as a convex region 226 that protrudes radially outward of the blade body 2 from a virtual arc line L1 passing through the cutting edge of the arc-shaped region E21 in the second region E2. This convex region 226 is formed in a curved shape having a convex vertex 226a in a region between the connection position with the first region E1 and the connection position with the arc-shaped region E21 of the second region E2. More specifically, the convex region 226 formed in a curved shape is smoothly inclined from the connection position with the first region E1 toward the convex vertex 226a, and is smoothly inclined from the convex vertex 226a toward the connection position with the arc-shaped region E21 of the second region E2. Also, as going from the connection position with the first region E1 toward the convex vertex 226a, the height from the virtual arc line L1 to the cutting edge gradually increases, and as going from the convex vertex 226a toward the connection position with the arc-shaped region E21 of the second region E2, the height from the virtual arc line L1 to the cutting edge gradually decreases.

[0040] Also, as shown in FIG. 7, the convex vertex 226a of the convex region 226 is disposed radially inward of the blade body 2 from a cutting edge line L2 which is a virtual line parallel to the virtual arc line L1 and passes through the cutting edge of the cutting edge generating blade 3.

[0041] The convex region 226 includes a first inclined region K1 going from the connection position with the arc-shaped region E21 of the second region E2 toward the convex vertex 226a, and a second inclined region K2 going from the convex vertex 226a toward the first region E1, and is configured such that the inclination angle of the second inclined region K2 is larger than the inclination angle of the first inclined region K1. Note that it is preferable to configure the first inclined region K1 and the arc-shaped region E21 of the second region E2 to be smoothly connected. Also, it is preferable to configure the second inclined region K2 and the first region E1 to be smoothly connected.

[0042] Further, in the present embodiment, a configuration is shown in which the third region E22 is arranged on one end side (the side where the cut generation blade 3 is arranged) rather than the intermediate position M between one end and the other end of the blade body 2. However, the present invention is not particularly limited to such a configuration, and a configuration in which the third region E22 is arranged in the intermediate position area between one end and the other end of the blade body 2 may be adopted.

[0043] The cutting tool 1 for cutting processing having the above configuration is used, for example, by being attached to a grooving device 70 (cutting device) as shown in FIGS. 19 and 20. 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, detailed description thereof is omitted here.

[0044] As described above, the cutting tool 1 for the present embodiment is configured such that, as the cutting edge shape of the grooving edge 22, it includes a recessed region 225 that is recessed inward in the radial direction of the tool body 2 from a virtual arc line L1 that passes through an arc-shaped cutting edge (the cutting edge related to the second region E2) having the same radius. Therefore, it is possible to effectively prevent damage such as fraying and skin peeling from occurring at the slit end formed by the cut generation edge 3. Hereinafter, such an effect will be specifically described with reference to FIG. 8 (a partial enlarged view) showing the state immediately before the cut generation edge 3 penetrates the cardboard sheet, and FIG. 9 showing the cut end face of the cardboard sheet during the slit processing in the state of FIG. 8. As shown in FIG. 9, immediately before the cut generation edge 3 penetrates the cardboard sheet, focusing on the connection portion Z1 where the separated slit chips are still connected to the cardboard sheet but neither side of the cardboard sheet has been cut yet, the first region E1 at the cutting edge of the grooving edge 22 does not bite into the cardboard sheet. As a result, the connection portion region Z1 becomes wider compared to the conventional cutting tool configuration for cutting. Thus, when the cutting edge of the cut generation edge 3 penetrates the cardboard sheet, the separated slit chip portion is stably held by the cardboard sheet, preventing the biting state of the cutting edge of the cut generation edge 3 from deteriorating when it penetrates the cardboard sheet, and realizing smooth cutting (penetration) by the cutting edge. Note that the first region E1 at the cutting edge of the grooving edge 22 enters the cardboard sheet as the cutting tool for cutting rotates after the penetration of the cardboard sheet by the cut generation edge 3 is completed, cutting the connection portion that has not been cut on both sides of the cardboard sheet, and separating the slit chips.

[0045] In this way, by performing slit processing in such a manner that after piercing the slit end with the cut generation edge 3, the connection portion Z1 that has not been cut on both sides of the cardboard sheet near the slit end is cut with the first region E1 of the cutting edge, it is possible to effectively prevent damage such as fraying and skin peeling from occurring at the slit end.

[0046] Also, like the cutting tool according to the second embodiment of the present invention, regarding the shape of the cutting edge of the grooving blade 22, the second region E2 includes a third region E22 that connects to the first region E1, and the third region E22 is formed as a convex region 226 that protrudes radially outward of the tool body 2 from a virtual arc line L1 passing through the arc-shaped cutting edge. As a result, it becomes possible to cut the end face (side face of the slit) of the slit more neatly.

[0047] The cutting tool 1 for cutting according to the first embodiment includes a second region E2 formed in an arc shape and a first region E1 as the shape of the cutting edge of the grooving blade 22. However, in such a configuration, after the cut generation blade 3 penetrates the cardboard sheet, as shown in FIG. 10, the connection portion of the separated slit scrap portion with the cardboard sheet is cut by a part of the second region E2 and the first region E1. However, it is feared that smooth cutting is not performed during this cutting and the cutting end face becomes slightly rough. On the other hand, like the cutting tool 1 for cutting according to the second embodiment, a third region E22 is formed as a convex region 226 that protrudes radially outward of the tool body 2 from a virtual arc line L1 passing through the arc-shaped cutting edge. By configuring the shape of the cutting edge of the grooving blade 22 to further include the third region E22, as shown in FIG. 11, the cutting edge related to the third region E22 that connects to the first region E1 can cut the cardboard sheet with the blade standing upright compared to the cutting tool 1 for cutting according to the first embodiment. Therefore, it becomes possible to cut the cardboard sheet extremely smoothly including the cutting edge portion of the first region E1, and it becomes possible to effectively prevent the cutting end face in the slit from becoming rough.

[0048] As described above, the cutting tool 1 according to the embodiment of the present invention has been described. However, the specific configuration of the cutting tool 1 is not limited to the above embodiment. In the above embodiment, the convex portion region 226 includes a first inclined region K1 extending from the connection position with the arc-shaped region E21 of the second region E2 toward the convex portion apex 226a, and a second inclined region K2 extending from the convex portion apex 226a toward the first region E1. The inclination angle of the second inclined region K2 is configured to be larger than the inclination angle of the first inclined region K1. However, the configuration is not particularly limited to this. The inclined shapes of the first inclined region K1 and the second inclined region K2 may be configured to be the same shape, or the inclination angle of the first inclined region K1 may be configured to be larger than the inclination angle of the second inclined region K2.

[0049] In addition, in the above-described embodiment, the cut generation blade 3 that cuts off one end of the chip produced when slit processing is performed by the cutting tool 1 is formed integrally with the tool body 2. However, the configuration is not particularly limited to this. For example, a configuration in which it is detachably attached to one end side of the tool body 2 can be adopted. When adopting a configuration in which the cut generation blade 3 is detachably attached to one end side of the tool body 2, for example, as shown in FIGS. 12(a) and 12(b), two bolt holes 21 are provided on one end side (one side surface side of the tool body 2) of the tool body 2, and the cut generation blade 3 configured separately is attached to the tool body 2 with bolts 50 through the bolt holes 21. Note that the two bolt holes 21 are preferably formed side by side along the radial direction of the tool body 2. Further, as the cut generation blade 3 configured to be detachable, for example, as shown in FIGS. 13(a) to 13(d), it 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. 13(a) is a plan view when the cut generation blade 3 is viewed from above, FIG. 13(b) is a side view viewed from the direction of arrow B in FIG. 13(a), FIG. 13(c) is a front view viewed from the direction of arrow C in FIG. 13(a), and FIG. 13(d) is a rear view viewed from the direction of arrow D in FIG. 13(a). The cut generation 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, for example, as shown in FIG. 12. The width of the cut generation blade 3 is preferably configured to be substantially the same 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. Note that the cut generation 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.

[0050] Further, in the cut generation blade 3 in FIG. 13, the through hole 33 is formed in a long hole shape along the radial direction of the blade body 2, and the mounting portion 31 (cut generation blade 3) is configured such that the cutting edge portion 32 can be adjusted in position in the radial direction of the blade body 2. That is, the dimension in the longitudinal direction of the long hole-shaped through hole 33 is configured to be longer than the distance between the two bolt holes 21 formed in the blade body 2 (the distance between the bolt holes 21 including the two bolt holes 21). The width dimension of the through hole 33 (in FIG. 13(a), the width dimension in the vertical direction) is set to be larger than the diameter of the shaft portion of the bolt 50 to be inserted. Note that the configuration is not particularly limited to being fixed to the blade body 2 by two bolts 50 while the cutting edge portion 32 of the cut generation blade 3 can be adjusted in position in the radial direction of the blade body 2, and a configuration in which the cut generation blade 3 is fixed to the blade body 2 so as to be adjustable in position in the radial direction of the blade body 2 by a single bolt 50 may be adopted.

[0051] Further, when the cut generation blade 3 is configured to be detachable, as the configuration of the cutting edge portion 32 of the cut generation blade 3, for example, as shown in FIG. 14, it may be configured in a semi-cylindrical form, and one end portion on the back surface side is cut out as shown by the broken lines in FIGS. 14(a) and 14(b), so that a semi-circular cutting edge is formed on the outer peripheral edge of one end. The cut generation blade 3 is attached to one end side of the blade body 2 with the outer peripheral curved surface of the cutting edge portion 32 exposed to one end side of the blade body 2. Here, FIG. 14(a) is a plan view when the cut generation blade 3 is viewed from above, FIG. 14(b) is a side view when viewed from the direction of arrow E shown in FIG. 14(a), FIG. 14(c) is a front view when viewed from the direction of arrow F shown in FIG. 14(a), and FIG. 14(d) is a rear view when viewed from the direction of arrow G shown in FIG. 14(a).

[0052] In addition, in the above-described embodiment, the cut generation blade 3 is configured to include a blade tip portion 32 as a flat blade. However, as shown in FIG. 15, one or more blade tip notches 321 may be formed in the blade tip portion 32. Note that FIG. 15 corresponds to a side view seen from the direction of arrow A1 in FIG. 2. Further, even when the cut generation blade 3 is configured in a semi-cylindrical shape as shown in FIG. 14 and a semi-circular blade tip is formed at one end outer peripheral edge thereof, one or more blade tip notches 321 may be formed in the blade tip (the tip of the blade tip portion 32).

[0053] In addition, in the above-described embodiment, as shown in FIG. 3, the groove cutting blade 22 having a V-shaped cross section is provided. However, the configuration is not particularly limited to this. For example, as shown in the schematic cross-sectional view of the main part enlarged in FIG. 16, 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 tool body 2 may be configured as blade tips 22a.

Explanation of Reference Numerals

[0054] 1 Cutting tool 2 Tool body 22 Groove cutting blade 225 Recessed area 225a Recessed vertex 226 Protruded area 226a Protruded vertex 3 Cut generation blade L1 Virtual arc line L2 A virtual line parallel to the virtual arc line L1 and passing through the blade tip of the cut generation blade (cutting blade tip line) E1 First region E2 Second region E21 Arc-shaped region E22 Third region K1 First inclined region K2 Second inclined region

Claims

1. A cutting tool for forming a slit in a sheet material, comprising: a tool body for forming the slit and a cut generating blade for forming an end of the slit; the tool body is formed in a fan shape and is provided with groove cutting blades respectively provided on both side edges in the thickness direction along its outer peripheral portion; the cut generating blade is configured to project outward in the radial direction of the tool body at one end side of the tool body; the cutting edge of the groove cutting blade includes a first region and a second region along the circumferential direction; the first region is a region connected to the cut generating blade; the second region is a region connected to the first region and extending from the connection position to the other end of the tool body; the second region is formed in an arc shape having the same radius; the first region is formed as a concave region recessed radially inward of the tool body with respect to a virtual arc line passing through the arc-shaped cutting edge, characterized in that it is a cutting tool for cutting.

2. The cutting tool for cutting according to claim 1, wherein the concave region is formed in a curved shape having a concave vertex in a region between the connection position with the second region and the connection position with the cut generating blade.

3. The cutting tool for cutting according to claim 2, wherein the concave region formed in the curved shape is formed to be smoothly inclined from the connection position with the second region toward the concave vertex and smoothly inclined from the concave vertex toward the connection position with the cut generating blade.

4. The cutting tool for cutting according to claim 1, wherein the cutting edge of the first region and the cut generating blade are smoothly connected.

5. The second region includes a third region connected to the first region; the cutting tool for cutting according to claim 1, wherein the third region is formed as a convex region protruding radially outward of the tool body with respect to a virtual arc line passing through the arc-shaped cutting edge.

6. The cutting tool for cutting according to claim 5, wherein the convex region is formed in a curved shape having a convex vertex in a region between the connection position with the first region and the connection position with the arc-shaped region of the second region.

7. The convex portion region formed in the curved shape is smoothly inclined from the connection position with the first region toward the apex of the convex portion, and is formed so as to be smoothly inclined from the apex of the convex portion toward the connection position with the arc-shaped region of the second region. The cutting tool according to claim 6, characterized in that.

8. The cutting tool according to claim 5, characterized in that the third region is disposed closer to one end than the intermediate position between one end and the other end of the tool body.

9. The cutting tool according to claim 6, characterized in that the apex of the convex portion region is disposed closer to the inner side in the radial direction of the tool body than a cutting edge tip line, which is a virtual line parallel to the arc line and passes through the cutting edge tip of the cut generation blade.

10. The convex portion region includes a first inclined region extending from the connection position with the arc-shaped region of the second region toward the apex of the convex portion, and a second inclined region extending from the apex of the convex portion toward the first region. The cutting tool according to claim 6, characterized in that the inclination angle of the second inclined region is larger than the inclination angle of the first inclined region.

11. The cutting tool according to claim 1, characterized in that each groove cutting 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.

12. The cutting tool according to claim 1, characterized in that the cut generation blade is integrally formed with the tool body.

13. The cutting tool according to claim 1, characterized in that the cut generation blade is configured to be detachably attachable to one end side of the tool body.

14. The cutting tool according to claim 1, characterized in that the cut generation blade includes a flat cutting edge portion.

15. The cutting tool according to claim 1, characterized in that the cut generation blade has a cutting edge notch at the tip of the cutting edge portion.

16. The cutting tool according to claim 1, characterized in that the cut generation blade includes a semi-cylindrical cutting edge portion.

17. The cutting tool according to claim 1, characterized in that the width of the cut generation blade is substantially the same as the thickness of the tool body.

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