Rotationally asymmetric cutting insert having a single radially extending cutting edge portion and rotary cutting tool

Abstract

A cutting insert (20) rotatable about an axis (A1) has opposing front and rear surfaces (22 and 24) interconnected by a peripheral insert surface (26) having first and second side surfaces (28, 30) separated by first and second land surfaces (32, 34). The first and second land edges (36, 38) extend along the first and second land surfaces, respectively. A first front edge (46) formed at the intersection of the front and first side surfaces includes a cutting edge portion (48), and a second front edge (52) formed at the intersection of the front and second side surfaces does not have a cutting edge portion. A cutting profile (PC) formed by rotating the cutting edge portion about the axis is located axially forward of the second front edge. The cutting insert (20) is releasably secured to a tool shank (66) with the cutting insert located between two protrusions (68, 70) projecting from a front end portion of the tool shank.

Description

Technical Field

[0001] The present invention relates to a cutting insert having a single radially extending cutting edge portion rotatable about an insert axis and a rotary cutting tool having such a cutting insert, which are generally used in metal cutting processes and in particular for drilling operations. Background Art

[0002] In the field of cutting tools used in drilling operations, there are many examples of rotary cutting tools having a cutting head, cutting plate or cutting tip having a single radially extending cutting edge portion, some of which are brazed or welded to a shank and some of which are capable of being removably replaced.

[0003] US Pat. No. 7,195,428 discloses a cutting tip bounded by an imaginary cylinder corresponding to the size of the hole to be drilled, having a generally V-shaped tip flute extending its entire length. The cutting tip is conventionally secured to the end of a shank by brazing or welding so that the tip flute is generally aligned with the shank flute. Pairs of raised, narrow, axially elongated wear pads are spaced around the periphery of the cutting tip, extending longitudinally and slightly raised relative to the adjacent cylindrical surface of the cutting tip.

[0004] US Pat. No. 7,296,953 discloses a deep-hole drill comprising a cutter carrier, replaceable cutting inserts, and at least one replaceable guide strip. The cutter carrier, in the form of a drill head, has a recess, wherein the rear surface and two side surfaces of the recess form a seat for a replaceable cutting plate. A central threaded hole in the rear surface receives a threaded element guided through a through hole in the replaceable cutting plate. Recesses for the guide strips are provided on the circumference of the drill at the axial height of the replaceable cutting plate seat, each guide strip abutting against a stop surface in a corresponding recess, and each stop surface has a central threaded hole for screwing into the corresponding guide strip.

[0005] US 7,393,162 discloses a gun drill comprising a cutting head removably secured to a shank, the cutting head having a common longitudinal axis and comprising mating peripheral surfaces. A shank coupling portion comprising a forwardly tapered shank mounting surface is formed at a front end portion of the shank, and a cutting head coupling portion comprising a forwardly tapered cutting head mounting surface is formed at a rear end portion of the cutting head. Both the shank and the cutting head coupling portion extend at a peripheral coupling angle exceeding 180 degrees. The shank and the cutting head are assembled by positioning the cutting head leading face in front of the rear end face of the shank; slidably inserting the cutting head coupling portion into the shank coupling portion laterally to the axis of rotation; and rotating the cutting head relative to the shank in a direction opposite to the direction of rotation so that the cutting head coupling portion and the shank coupling portion coaxially interlock.

[0006] An object of the present invention is to provide an improved cutting insert rotatable about an insert axis having a single radially extending cutting edge portion.

[0007] It is also an object of the present invention to provide an improved cutting insert for drilling operations, in which radial support within the workpiece is provided integrally.

[0008] It is a further object of the present invention to provide an improved rotary cutting tool having a cutting insert releasably secured to a tool shank. Summary of the Invention

[0009] According to the present invention, there is provided a rotationally asymmetric cutting insert rotatable in a cutting rotation direction about an insert axis defining an insert forward-backward direction, the cutting insert comprising;

[0010] opposed front and rear surfaces interconnected by a blade peripheral surface having first and second side surfaces separated by first and second land surfaces,

[0011] a first land edge extending rearwardly from the front surface along the first land surface,

[0012] a second land edge extending rearwardly from the front surface along the second land surface;

[0013] a first leading edge formed at a junction of the front surface and the first side surface, the first leading edge including a cutting edge portion extending in a radial direction; and

[0014] a second front edge formed at a junction of the front surface and the second side surface, the second front edge having no cutting edge portion,

[0015] in:

[0016] The first side surface includes a rake surface adjacent to the cutting edge portion, the rake surface facing the cutting rotation direction;

[0017] The first and second land edges are received in an envelope surface of an imaginary first cylinder having a circular cross-section and a cylinder axis coaxial with the insert axis, the imaginary first cylinder having a first diameter, and

[0018] An imaginary cutting profile formed by rotating the cutting edge portion 360 degrees about the insert axis is located axially forward of the second leading edge and defines a cutting diameter corresponding to the first diameter.

[0019] In addition, according to the present invention, there is provided a rotary cutting tool comprising:

[0020] a tool shank extending along a shank axis defining a forward-rearward direction of the shank, the tool shank including first and second spaced-apart projections projecting from a forward end portion thereof, and a blade receiving slot located between the first and second projections; and

[0021] A rotationally asymmetric cutting insert of the above type, releasably secured to a tool shank in an insert receiving pocket,

[0022] in:

[0023] The blade axis is coaxial with the handle axis; and

[0024] The front surface of the blade faces in a forward direction of the handle. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a better understanding, the invention will now be described, by way of example only, with reference to the accompanying drawings in which dot-dash lines indicate cut-off boundaries of partial views of components, and in which:

[0026] Figure 1 is a perspective view of a cutting insert according to some embodiments of the present invention;

[0027] Figure 2 yes Figure 1 A front view of the cutting insert shown in ;

[0028] Figure 3 yes Figure 1 A first side view of the cutting insert shown in ;

[0029] Figure 4 yes Figure 1 a second side view of the cutting insert shown in ;

[0030] Figure 5 yes Figure 1 a third side view of the cutting insert shown in FIG;

[0031] Figure 6 yes Figure 1 a fourth side view of the cutting insert shown in ;

[0032] Figure 7 is a first perspective view of a rotary cutting tool according to some embodiments of the present invention;

[0033] Figure 8 yes Figure 7 a second perspective view of the rotary cutting tool shown in ;

[0034] Figure 9 yes Figure 7 An exploded perspective view of a rotary cutting tool shown in ;

[0035] Figure 10 yes Figure 7 a front view of the rotary cutting tool shown in ; and

[0036] Figure 11 is a front end view of a tool shank according to some embodiments of the present invention; and

[0037] Figure 12 It is taken along line XII-XII Figure 11 A cross-sectional view of the tool shank is shown in FIG. DETAILED DESCRIPTION

[0038] A first aspect of the present invention relates to a cutting insert 20 having opposed front and rear surfaces 22, 24 interconnected by an insert peripheral surface 26, and an insert axis AI defining an insert forward-rearward direction IF, IR.

[0039] like Figures 1 to 6 , the cutting insert 20 is rotatable about an insert axis AI in a cutting rotation direction RC, and the insert peripheral surface 26 has a first side surface 28 and a second side surface 30 separated by a first land surface 32 and a second land surface 34. The cutting insert 20 is rotationally asymmetric about the insert axis AI (except for rotations of multiples of 360 degrees).

[0040] In some embodiments of the present invention, the cutting insert 20 may preferably be manufactured by form pressing and sintering a cemented carbide such as tungsten carbide, and may be coated or uncoated.

[0041] Additionally, in some embodiments of the present invention, the cutting insert 20 may have a unitary, one-piece construction.

[0042] like Figures 1 to 6 As shown in FIG, first land edge 36 extends rearwardly from front surface 22 along first land surface 32 , and second land edge 38 extends rearwardly from front surface 22 along second land surface 34 .

[0043] like Figure 2 As shown in FIG, the first land edge 36 and the second land edge 38 are received in an envelope surface 40 of an imaginary first cylinder C1 having a circular cross section and a cylinder axis AC coaxial with the insert axis AI, the imaginary first cylinder C1 having a first diameter D1.

[0044] It should be appreciated throughout the description and claims that the imaginary first cylinder C1 may undergo a slight axial taper in the rearward direction IR such that the first diameter D1 decreases by at most 0.01 mm along the length of the first land edge 36 .

[0045] In some embodiments of the present invention, a first land edge 36 may be formed at the junction of the first side surface 28 and the first land surface 32 , and a second land edge 38 may be formed at the junction of the second side surface 30 and the second land surface 34 .

[0046] like Figure 3 and Figure 5 As shown in FIG, the first land edge 36 extends rearwardly from the first end point N1.

[0047] In some embodiments of the present invention, Figure 2 As shown in , the first end point N1 and the insert axis AI may be accommodated in a first insert plane PI1 .

[0048] Additionally, in some embodiments of the present invention, the first land edge 36 may be straight and parallel to the insert axis AI.

[0049] Further, in some embodiments of the present invention, the first land edge 36 may intersect the rear surface 24 .

[0050] like Figure 2 and Figure 6 As shown in , the second land surface 34 may include a first support surface 42 that is received in the envelope surface 40 of the imaginary first cylinder C1 .

[0051] In some embodiments of the present invention, the first support surface 42 may extend circumferentially from the second land edge 38 in a direction opposite to the cutting rotation direction RC.

[0052] like Figure 2 As shown in the figure, the first support surface 42 can be completely located in the first imaginary quadrant Q1 of the four imaginary quadrants Q1, Q2, Q3, and Q4, and the four imaginary quadrants Q1, Q2, Q3, and Q4 are defined by a first blade plane PI1, which intersects with a second blade plane PI2 perpendicular to the first blade plane PI1 and accommodates the blade axis AI.

[0053] In some embodiments of the present invention, the first support surface 42 may intersect the front surface 22 .

[0054] Additionally, in some embodiments of the present invention, the first support surface 42 may intersect the rear surface 24 .

[0055] like Figure 2 and Figure 6 As shown in FIG, the first support surface 42 may be spaced apart from the first side surface 28 by a first intermediate surface 44 .

[0056] In some embodiments of the present invention, the first intermediate surface 44 may be located radially inward of the envelope surface 40 of the imaginary first cylinder C1 .

[0057] Additionally, in some embodiments of the present invention, the first intermediate surface 44 may be planar, in the form of an axially extending inclined surface.

[0058] like Figures 1 to 6 As shown in FIG, the first leading edge 46 is formed at the junction of the front surface 22 and the first side surface 28, and the first leading edge 46 includes a cutting edge portion 48 extending in the radial direction.

[0059] In some embodiments of the present invention, the cutting edge portion 48 may extend radially outward to the first land edge 36 .

[0060] like Figure 2 As shown in , the cutting edge portion 48 may have a radially outermost cutting point NRO received within the envelope surface 40 of the imaginary first cylinder C1.

[0061] It should be appreciated that in some embodiments of the present invention, the radially outermost cutting point NRO may coincide with the first endpoint N1 of the first land edge 36 .

[0062] like Figures 1 to 3 As shown in FIG, the first side surface 28 includes a rake face 50 adjacent to the cutting edge portion 48 facing the cutting rotation direction RC.

[0063] In some embodiments of the present invention, the rake surface 50 may be a planar sub-surface of the first side surface 28 .

[0064] In other embodiments of the present invention (not shown), the rake surface 50 may include a recess or a plurality of recesses in the first side surface 28 .

[0065] like Figure 1 、 Figure 2 and Figure 4 As shown in FIG, the front surface 22 includes a relief surface 51 adjacent to the cutting edge portion 48.

[0066] In some embodiments of the present invention, the relief surface 51 may be multi-faceted.

[0067] According to the present invention, a second front edge 52 is formed at the junction of the front surface 22 and the second side surface 30, and the second front edge 52 has no cutting edge portion.

[0068] Given that the first leading edge 46 has a radially extending cutting edge portion 48 and the second leading edge 52 has no cutting edge portion, the cutting insert 20 may be referred to as having a single radially extending cutting edge portion.

[0069] like Figures 1 to 6As shown in , the cutting insert 20 may not exhibit rotational symmetry about the insert axis AI. As such, the cutting insert 20 is considered to be rotationally asymmetric about the insert axis A1.

[0070] like Figure 3 and Figure 4 As shown in FIG, an imaginary cutting profile PC formed by rotating the cutting edge portion 48 360 degrees about the insert axis AI is located axially forward of the entire second leading edge 52.

[0071] It should be appreciated throughout the description and claims that the relative axial position of the second leading edge 52 with respect to the imaginary cutting profile PC is considered to be at equivalent radial extents of the second leading edge 52 and the imaginary cutting profile PC from the insert axis AI.

[0072] In some embodiments of the present invention, the imaginary cutting profile PC may be located axially forward of any edge associated with the front surface 22, other than the cutting edge portion 48 itself that defines the imaginary cutting profile PC.

[0073] Additionally, in some embodiments of the present invention, the imaginary cutting profile PC may define a cutting diameter DC corresponding to the first diameter D1.

[0074] Further, in some embodiments of the present invention, the cutting edge portion 48 may extend radially outward from the insert axis AI.

[0075] like Figures 2 to 4 As shown in , the cutting edge portion 48 may have a radially innermost cutting point NRI that coincides with the insert axis AI.

[0076] It should be appreciated that in some embodiments of the present invention, the radially innermost cutting point NRI may also coincide with the center point NC of the imaginary cutting profile PC.

[0077] In some embodiments of the present invention, the radially innermost cutting point NRI may be located axially forward of the radially outermost cutting point NRO.

[0078] like Figures 2 to 4 As shown in , the cutting edge portion 48 may have an axially forward-most cutting point NF that is radially midway between the insert axis AI and the envelope surface 40 of the imaginary first cylinder C1.

[0079] For embodiments of the present invention in which the cutting insert 20 has an integral one-piece construction and is manufactured by forming, pressing and sintering cemented carbide, it should be appreciated that by applying post-sintering process steps (e.g., grinding), multiple insert sizes of different cutting diameters DC can be advantageously produced from the same size formed and pressed body.

[0080] like Figure 2As shown in FIG, the first insert plane PI1 can accommodate the entire cutting edge portion 48.

[0081] In some embodiments of the present invention, the first blade plane PI1 may accommodate the entire first leading edge 46 .

[0082] Additionally, in some embodiments of the present invention, the first side surface 28 may be planar.

[0083] Further, in some embodiments of the present invention, the cutting insert 20 may be used in drilling operations, whereby radial support within a workpiece (not shown) is advantageously provided by at least the integrally formed first support surface 42 .

[0084] It will be appreciated that the aforementioned slight axial tapering of the imaginary first cylinder C1 in the rearward direction IR is particularly suitable for the configuration of the cutting insert 20 for drilling operations.

[0085] like Figure 2 、 Figure 5 and Figure 6 As shown in , the shoulder portion 54 may protrude from the second side surface 30 .

[0086] In some embodiments of the present invention, the shoulder portion 54 may have a second support surface 56 that is received in the envelope surface 40 of the imaginary first cylinder C1 .

[0087] Additionally, in some embodiments of the present invention, the second support surface 56 may intersect the front surface 22 .

[0088] like Figure 2 As shown in , the second support surface 56 may be located entirely within a second imaginary quadrangle Q2 that is adjacent to the first imaginary quadrangle Q1 and is separated from the first imaginary quadrangle Q1 by a second blade plane PI2.

[0089] For embodiments of the present invention having at least two integrally formed support surfaces (i.e., first support surface 42 and second support surface 56 located in adjacent first and second quadrants Q1 and Q2, respectively), a high level of radial support is provided within a drilled hole in a workpiece (not shown).

[0090] like Figure 1 、 Figure 2 and Figure 5 As shown in , the first land surface 32 may include a third support surface 58 received in the envelope surface 40 of the imaginary first cylinder C1.

[0091] In some embodiments of the present invention, the third support surface 58 may extend circumferentially from the first land edge 36 in a direction opposite to the cutting rotation direction RC.

[0092] Additionally, in some embodiments of the present invention, the third support surface 58 may intersect the front surface 22 .

[0093] Further, in some embodiments of the present invention, the third support surface 58 may intersect the rear surface 24 .

[0094] like Figure 1 、 Figure 2 and Figure 5 As shown in FIG, the second support surface 56 may be spaced apart from the third support surface 58 by a second intermediate surface 60 .

[0095] In some embodiments of the present invention, Figure 2 As shown in FIG, the second intermediate surface 60 may be located radially inward of the envelope surface 40 of the imaginary first cylinder C1.

[0096] Additionally, in some embodiments, the shoulder portion 54 may be joined to the first land surface 32 via a second intermediate surface 60 .

[0097] Further, in some embodiments of the present invention, the second intermediate surface 60 may be planar.

[0098] like Figure 2 As shown in , for embodiments of the present invention that include the third support surface 58 , the third support surface 58 may be located entirely within the second imaginary quadrant Q2 .

[0099] An embodiment of the present invention has three integrally formed support surfaces (i.e., the first support surface 42, the second support surface 56, and the third support surface 58) located in the first imaginary boundary Q1 and the second imaginary boundary Q2, so that the two imaginary boundaries Q3 and Q4 located on opposite sides of the first blade plane PI1 have no support surfaces. For the embodiment, sufficient lateral movement of the cutting insert 20 perpendicular to the insert axis AI can be achieved in the workpiece, so that the cutting insert 20 can be released from the workpiece without getting stuck.

[0100] like Figure 2 、 Figure 4 and Figure 6 As shown in , the shoulder portion 54 may include an abutment surface 62 facing away from the first land surface 32 .

[0101] In some embodiments of the present invention, the abutment surface 62 may be located radially inward of the envelope surface 40 of the imaginary first cylinder C1 , adjacent to the second support surface 56 .

[0102] Additionally, in some embodiments of the present invention, the abutment surface 62 may be located in the second imaginary quadrant Q2, facing the second blade plane PI2.

[0103] Further, in some embodiments of the present invention, the abutment surface 62 may be planar.

[0104] Still further, in some embodiments of the present invention, the abutment surface 62 may be inclined at an abutment angle α1 of less than 10 degrees relative to the second blade plane PI2 when viewed along the insert axis AI.

[0105] In other embodiments of the present invention (not shown), the abutment surface 62 may be parallel to the second blade plane PI2.

[0106] A second aspect of the present invention relates to a rotary cutting tool 64 having a tool shank 66 extending along a shank axis AS defining a shank forward-rearward direction SF, SR, and a cutting insert 20 releasably secured to the tool shank 66.

[0107] like Figures 7 to 12 As shown in FIG, the tool shank 66 has spaced-apart first and second ridges 68, 70 projecting from a forward end portion 72 thereof, with the cutting insert 20 positioned in an insert receiving slot 74 between the first and second ridges 68, 70.

[0108] In some embodiments of the present invention, the tool shank 66 may include at least one coolant passage 75 a , 75 b extending axially through the first protuberance 68 .

[0109] like Figure 7 and Figure 8 As shown, the insert axis AI is coaxial with the handle axis AS, and the front surface 22 of the insert faces in the handle forward direction SF.

[0110] It should be appreciated that when retained in the tool shank 66, at least a portion of the front surface 22 of the insert may be positioned axially forward of the first and second protrusions 68, 70 to an extent that allows for regrinding of the front surface 22 and reuse of the cutting insert 20 after the original cutting edge portion 48 has worn and / or become damaged.

[0111] In some embodiments of the present invention, the tool shank 66 may have a generally cylindrical shank peripheral surface 76 having a shank diameter DS, and the shank diameter DS may be smaller than the first diameter D1.

[0112] Additionally, in some embodiments of the present invention, a shank flute 78 may be formed in the shank peripheral surface 76 extending rearwardly from the front end portion 72 .

[0113] like Figure 11 As shown in , the shank flutes 78 may be substantially V-shaped when viewed along the shank axis AS.

[0114] Although not shown in the figures, it will be appreciated that the shank flutes 78 may not extend along the entire axial length of the tool shank 66 .

[0115] In some embodiments of the present invention, the rotary cutting tool 64 may be used for drilling operations.

[0116] Additionally, in some embodiments of the present invention, the rotary cutting tool 64 may be used to drill a hole having a substantial depth relative to the cutting diameter DC, ie, deep drilling, also known as deep hole drilling.

[0117] It will be appreciated that by positioning the cutting insert 20 in the insert receiving slot 74 between the axially forwardly projecting first and second protrusions 68, 70, there is no risk of the cutting insert 20 accidentally becoming detached from the tool shank 66 during brief reverse rotation of the rotating cutting tool 64 in the workpiece, in contrast to the gun drill of US 7,393,162 mentioned above, in which the cutting head disclosed in US 7,393,162 is detachably secured to the shank disclosed therein by relative rotation about a longitudinal axis of rotation.

[0118] like Figures 1 to 3 As shown in FIG, the first side surface 28 of the insert may include a first mounting surface 80 facing in a direction opposite to the cutting rotation direction RC.

[0119] In some embodiments of the present invention, the first mounting surface 80 may intersect the second land surface 34 .

[0120] Additionally, in some embodiments of the present invention, the first mounting surface 80 may be a planar sub-surface of the first side surface 28 .

[0121] like Figure 10 As shown in FIG, the first clamping surface 81 of the first protrusion 68 may contact the first mounting surface 80 .

[0122] like Figure 4 As shown in FIG, the second side surface 30 of the blade may include three coplanar second mounting surfaces 82a, 82b, 82c that are spaced apart from one another.

[0123] In some embodiments of the present invention, the three second mounting surfaces 82 a , 82 b , 82 c may be parallel to the first mounting surface 80 .

[0124] It will be appreciated that the provision of three co-planar second mounting surfaces 82a, 82b, 82c advantageously facilitates the fabrication of the first mounting surface 80 parallel thereto.

[0125] like Figure 10 As shown in FIG, the second clamping surface 83 of the second protrusion 70 may contact at least one of the three second mounting surfaces 82a, 82b, 82c.

[0126] In some embodiments of the present invention, the second clamping surface 83 may face the first clamping surface 81 .

[0127] like Figure 3 and Figure 4 As shown in FIG, the blade opening 84 may extend from the first side surface 28 of the blade to the second side surface 30 of the blade.

[0128] In some embodiments of the present invention, the blade opening 84 may be positioned asymmetrically relative to the blade axis AI.

[0129] Additionally, in some embodiments of the present invention, the blade opening 84 may extend to the rear surface 24. Thus, the blade opening 84 may be open to the first and second side surfaces 28, 30 of the blade and also open to the rear surface 24 of the blade.

[0130] For embodiments of the present invention where the blade opening 84 extends to the rear surface 24, the blade opening 84 may have an elongated slot shape.

[0131] Additionally, for embodiments of the present invention in which the blade opening 84 extends to the rear surface 24, the rear surface 24 may include two spaced-apart rear subsurfaces 24a, 24b.

[0132] In other embodiments of the present invention (not shown), the blade opening 84 may be in the form of a blade through-hole extending from the first side surface 28 to the second side surface 30 .

[0133] like Figures 8 to 10 As shown in FIG, a clamping bolt 86 may extend through the blade opening 84 and clamp the first and second ridges 68, 70 against the first and second side surfaces 28, 30 of the blade, respectively.

[0134] In some embodiments of the present invention, the blade opening 84 may open to the first mounting surface 80 of the first side surface 28 of the blade.

[0135] It will be appreciated that configuring the insert opening 84 to be asymmetrically positioned relative to the insert axis AI may advantageously reduce the risk of incorrectly assembling the rotary cutting tool 64 .

[0136] In some embodiments of the present invention, the clamping bolt 86 may extend through a shank through-hole 88 in the second protuberance 70 and threadingly engage a shank threaded internal bore 90 in the first protuberance 68 .

[0137] It should be appreciated that for embodiments of the present invention in which the blade opening 84 extends to the rear surface 24 rather than being in the form of a through-blade hole, the cutting blade 20 can be removed and replaced without disengaging the clamping bolt 86 from the shank threaded inner bore 90 in the first protrusion 68. Instead, the cutting blade 20 can be removed and replaced simply by releasing the clamping force between the first protrusion 68 and the second protrusion 70.

[0138] In some embodiments of the present invention, the second protuberance 70 may include a countersunk hole 92 coaxial with the shank through-hole 88 and open to the shank peripheral surface 86 .

[0139] It should be appreciated that the countersunk bore 92 may have a larger diameter than the shank through-bore 88 in order to provide sufficient space for the bolt head 94 of the clamping bolt 86 .

[0140] like Figure 7 As shown in FIG, the rear surface 24 of the blade may contact the bottom surface 96 of the blade-receiving slot 74.

[0141] For embodiments of the present invention where the rear surface 24 includes two spaced-apart rear sub-surfaces 24 a , 24 b , two coplanar areas of the rear sub-surfaces 24 a , 24 b may contact the bottom surface 96 of the blade-receiving slot 74 .

[0142] In some embodiments of the present invention, the rear surface 24 of the insert may be inclined from the first land surface 32 to the second land surface 34 in the insert rearward direction IR.

[0143] For such embodiments of the present invention in which the rear surface 24 of the insert is inclined in the insert rearward direction IR from the first land surface 32 to the second land surface 34, the bottom surface 96 of the insert receiving pocket may be correspondingly inclined therewith.

[0144] It will be appreciated that configuring the rear surface 24 of the insert to be beveled may advantageously reduce the risk of incorrectly assembling the rotary cutting tool 64 .

[0145] like Figure 10 As shown in FIG, the abutment surface 62 of the shoulder portion 54 of the blade may contact the abutment wall 98 of the second protuberance 70 .

[0146] It should be appreciated that during assembly of the rotary cutting tool 64, when the tool shank 66 is oriented in an “upright” position, i.e., with the forward direction SF of the shank opposite the direction of gravity, the inclination of the rear surface 24 of the insert and the bottom surface 96 of the insert receiving slot advantageously promotes contact between the abutment surface 62 and the abutment wall 98.

[0147] It will also be appreciated that the inclination of the rear surface 24 of the insert and the bottom surface 96 of the insert receiving pocket may advantageously facilitate contact between the abutment surface 62 and the abutment wall 98 during use of the rotary cutting tool 64 in a drilling operation.

[0148] In some embodiments of the present invention, it will be appreciated that due to manufacturing tolerances and errors, the abutment surface 62 may only contact the vertical edge 99 of the abutment wall 98 .

[0149] like Figure 11 and Figure 12 As shown in FIG, a first shank plane PS1 parallel to the shank axis AS bisects the insert receiving slot 74 along its length, and the first and second ridges 68, 70 are located on opposing first and second planar sides S1, S2, respectively, of the first shank plane PS1.

[0150] In some embodiments of the present invention, the shank flutes 78 may be located on a first planar side S1 of the first shank plane PS1.

[0151] Additionally, in some embodiments of the present invention, the handle axis AS may be located on a first planar side S1 of the first handle plane PS1.

[0152] Furthermore, in some embodiments of the present invention, the first blade plane PI1 may be parallel to the first shank plane PS1 and offset from the first shank plane PS1.

[0153] Still further, in some embodiments of the present invention, the shank flute 78 may be in communication with the insert receiving slot 74 .

[0154] Although the present invention has been described with a certain degree of detail, it should be understood that various changes and modifications could be made without departing from the spirit or scope of the invention as claimed.

Claims

1. A rotationally asymmetric cutting insert (20), the cutting insert (20) being rotatable in a cutting rotation direction (RC) about an insert axis (AI) defining an insert forward-rearward direction (IF, IR), the cutting insert (20) comprising: Opposed front and rear surfaces (22) and (24) interconnected by a blade peripheral surface (26) having first and second side surfaces (28, 30) separated by first and second land surfaces (32, 34), a first land edge (36) formed at a junction of the first side surface (28) and the first land surface (32) and extending rearwardly along the first land surface (32) from a first end point (N1) located on the front surface (22), a second land edge (38) formed at a junction of the second side surface (30) and the second land surface (34) and extending rearwardly from the front surface (22) along the second land surface (34); a first leading edge (46) formed at the intersection of the leading surface (22) and the first side surface (28), the first leading edge (46) including a cutting edge portion (48) extending radially outward to the first land edge (36); and a second front edge (52) formed at the junction of the front surface (22) and the second side surface (30), the second front edge (52) having no cutting edge portion, a first blade plane (PI1), said first blade plane (PI1) accommodating said blade axis (AI) and said first end point (N1); a second blade plane (PI2), said second blade plane (PI2) being perpendicular to said first blade plane (PI1) and also accommodating said blade axis (AI), said second blade plane (PI2) intersecting said first blade plane (PI1) thereby forming a first imaginary quadrant (Q1), a second imaginary quadrant (Q2), a third imaginary quadrant (Q3) and a fourth imaginary quadrant (Q4); wherein: The first side surface (28) includes a rake face (50) adjacent to the cutting edge portion (48), the rake face (50) facing in the cutting rotation direction (RC); The first land edge (36) and the second land edge (38) are housed in an envelope surface (40) of an imaginary first cylinder (C1) having a circular cross section and a cylinder axis (AC) coaxial with the insert axis (AI), the imaginary first cylinder (C1) having a first diameter (D1), an imaginary cutting profile (PC) formed by rotating the cutting edge portion (48) 360 degrees about the insert axis (AI) located axially forward of the second leading edge (52) and defining a cutting diameter (DC) corresponding to the first diameter (D1), The second land surface (34) includes a first support surface (42) received in an envelope surface (40) of the imaginary first cylinder (C1), and In a front view of the cutting insert (20), the first support surface (42) is completely located in the first imaginary quadrant (Q1).

2. The cutting insert (20) according to claim 1, wherein The imaginary cutting profile (PC) is located axially forward of any edge associated with the front surface (22), except for the cutting edge portion (48).

3. The cutting insert (20) according to claim 1, wherein The first land edge (36) is straight and parallel to the insert axis (AI).

4. The cutting insert (20) according to claim 1, wherein The cutting edge portion (48) extends radially outward from the insert axis (AI).

5. The cutting insert (20) according to claim 1, wherein The entire cutting edge portion (48) is accommodated in the first insert plane (PI1).

6. The cutting insert (20) according to claim 1, wherein: A shoulder portion (54) protrudes from the second side surface (30), and The shoulder portion (54) has a second support surface (56) received in the envelope surface (40) of the imaginary first cylinder (C1).

7. The cutting insert (20) according to claim 6, wherein: The second support surface (56) is located entirely in a second imaginary quadrant (Q2) which is circumferentially adjacent to the first imaginary quadrant (Q1) and is separated from the first imaginary quadrant (Q1) by a second blade plane (PI2).

8. The cutting insert (20) according to claim 7, wherein: The first land surface (32) includes a third support surface (58) received in the envelope surface (40) of the imaginary first cylinder (C1), and The third support surface (58) is located entirely within the second imaginary quadrant (Q2).

9. The cutting insert (20) according to claim 1, wherein The cutting edge portion (48) has an axially forward cutting point (NF) which is radially located midway between the insert axis (AI) and the envelope surface (40) of the imaginary first cylinder (C1).

10. The cutting insert (20) according to claim 1, wherein A blade opening (84) extends from the first side surface (28) to the second side surface (30).

11. The cutting insert (20) according to claim 10, wherein The blade opening (84) is asymmetrically positioned relative to the blade axis (AI).

12. A rotary cutting tool (64), comprising: a tool shank (66) extending along a shank axis (AS) defining a forward-rearward direction (SF, SR) of the shank, the tool shank (66) including first and second spaced-apart ridges (68, 70) projecting from a forward end portion (72) thereof, and a blade receiving slot (74) located between the first and second ridges (70); and The rotationally asymmetric cutting insert (20) of claim 1, releasably secured to the tool shank (66) in the insert receiving slot (74), in: The blade axis (AI) is coaxial with the shank axis (AS); and The front surface (22) of the blade faces in a forward direction (SF) of the handle.

13. The rotary cutting tool (64) of claim 12, wherein: The tool shank (66) has a generally cylindrical shank peripheral surface (76) having a shank diameter (DS) that is smaller than the first diameter (D1), and Shank flutes (78) are formed in the shank peripheral surface (76) extending rearwardly from the front end portion (72).

14. The rotary cutting tool (64) of claim 12, wherein: The cutting insert (20) has an insert opening (84) extending from a first side surface (28) of the insert to a second side surface (30) of the insert, and A clamping bolt (86) extends through the blade opening (84) and clamps the first and second ridges (68, 70) against the first and second side surfaces (28, 30) of the blade, respectively.

15. The rotary cutting tool (64) of claim 12, wherein: The blade receiving slot (74) has a bottom surface (96), The rear surface (24) of the blade contacts the bottom surface (96) of the blade receiving slot, The rear surface (24) of the insert is inclined in the insert rearward direction (IR) from the first land surface (32) to the second land surface (34), and The bottom surface (96) of the blade receiving slot is inclined correspondingly to the rear surface (24) of the blade.

16. The rotary cutting tool (64) of claim 12, wherein: The second protuberance (70) of the handle has an abutment wall (98), The cutting insert (20) has a shoulder portion (54) projecting from the second side surface (30), the shoulder portion (54) including an abutment surface (62) facing away from the first land surface (32), and The abutment surface (62) contacts an abutment wall (98) of the second protrusion (70).

17. The rotary cutting tool (64) of claim 12, wherein: The first protrusion (68) of the handle has a first clamping surface (81), The first side surface (28) of the insert includes a first mounting surface (80) facing in a direction opposite to the cutting rotation direction (RC), and A first clamping surface (81) of the first protrusion (68) contacts the first mounting surface (80).

18. The rotary cutting tool (64) of claim 17, wherein: The second protuberance (70) of the handle has a second clamping surface (83), The second side surface (30) of the blade includes three coplanar second mounting surfaces (82a, 82b, 82c), and the second clamping surface (83) of the second protrusion (70) contacts at least one of the three second mounting surfaces (82a, 82b, 82c).

19. The rotary cutting tool (64) of claim 18, wherein: The three second mounting surfaces (82a, 82b, 82c) are parallel to the first mounting surface (80).

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