A cutting insert having two upper cutting edges and a lower central protuberance with four abutting walls defining an imaginary rectangle, and a rotary cutting tool

Abstract

The cutting insert has opposing upper and lower side surfaces interconnected by an outer peripheral side surface, an insert axis passing through the upper and lower side surfaces, and first and second upper cutting edges formed at an intersection of the upper and lower side surfaces. A lower central ridge having first, second, third, and fourth abutment walls extends downward from the lower side surface. In a cross section taken along a first horizontal plane perpendicular to the insert axis and intersecting the lower central ridge, the first, second, third, and fourth abutment walls define an imaginary rectangle, the imaginary rectangle having diagonally opposite first and third interior angles and diagonally opposite second and fourth interior angles. The first and third interior angles are equal to each other, and the second and fourth interior angles are unequal to each other. The two cutting inserts are removably secured within a rotary cutting tool.

Description

[Technical field]

[0001] The present invention relates to a rotary cutting tool and cutting insert having two upper cutting edges and a lower central raised portion with four abutting walls defining an imaginary rectangle, the rotary cutting tool being for use in milling operations in general, and in particular in the form of a ballnose end mill for contouring and profiling operations. [Background technology]

[0002] In the field of cutting tools used in milling operations, there are several examples of cutting inserts having two upper cutting edges and a lower central ridge with four abutting walls defining an imaginary square.

[0003] US 6,536,996 discloses a cutting tool comprising a tool body and two cutting inserts assembled in the tool body. An insert-receiving pocket in the tool body has a pocket bottom wall. A recess opening into the pocket bottom wall has a lower side wall bounded by a first side wall, a second side wall, a third side wall and a fourth side wall. The cutting insert has an insert bottom wall. A raised portion extends downwardly from the insert bottom wall and has a lower side wall bounded by a first lateral wall, a second lateral wall, a third lateral wall and a fourth lateral wall. The insert bottom wall abuts the pocket bottom wall, the first lateral wall abuts the first side wall, the third lateral wall abuts the third side wall, the first lateral wall is a first distance away from the centerline, the cutting edge proximate to the centerline is a second distance away from the centerline, the first distance being at least three times greater than the second distance, and the clearance face of the cutting insert is free from the insert-receiving pocket.

[0004] US9,573,204 discloses a cutting tool and a cutting insert, each including a bottom surface and an anti-slip arrangement adjacent to the bottom surface. The anti-slip arrangement of the cutting insert includes an insert working surface and a first and a second insert abutment surface that are not parallel, the first and the second insert abutment surface being formed on one ridge in a central region of the insert bottom surface. The anti-slip arrangement of the tool includes a first and a second tool abutment surface that are recessed into the tool bottom surface and a fastener with the tool working surface. The cutting insert is assembled on the cutting tool via engagement of the bottom surface of the cutting insert, and the fastener is operable to bias the working surfaces against each other, thereby forcing the first and the second abutment surfaces against each other and preventing the cutting insert from sliding along the bottom surface of the tool. Summary of the Invention

[0005] It is an object of the present invention to provide an improved cutting insert having an optimized peripheral geometry.

[0006] It is also an object of the present invention to provide an improved rotary cutting tool having two identical cutting inserts removably secured therein.

[0007] It is a further object of the present invention to provide an improved rotary cutting tool which can perform a cutting action by axially advancing along the tool axis and which does not leave an uncut "midfoot" in the workpiece.

[0008] It is yet a further object of the present invention to provide an improved rotary cutting tool in which two cutting inserts have non-identical effective cutting edges and two insert-receiving pockets provide equal levels of radial and axial support for the cutting inserts.

[0009] It is still a further object of the present invention to provide an improved rotary cutting tool in which each cutting insert may be removably secured within only one of two insert-receiving pockets in a single assembly position.

[0010] According to the present invention, there is provided a cutting insert, the cutting insert comprising: opposing upper and lower sides interconnected by a peripheral side and an insert axis passing through the upper and lower sides; an upper outer peripheral edge portion at an intersection line between the upper surface and the outer peripheral surface, the upper outer peripheral edge portion having a first upper cutting edge and a second upper cutting edge; a lower central ridge extending downwardly from the lower surface and away from the upper surface; the lower central ridge includes a first abutment wall, a second abutment wall, a third abutment wall, and a fourth abutment wall across the lower surface, the first abutment wall, the second abutment wall, the third abutment wall, and the fourth abutment wall being successively arranged on an envelope surface extending around a periphery of the lower central ridge; In a cross section taken on a first horizontal plane perpendicular to the insert axis and intersecting the envelope surface, the first abutment wall, the second abutment wall, the third abutment wall and the fourth abutment wall define an imaginary rectangle, the imaginary rectangle having diagonally opposite first and third interior angles and diagonally opposite second and fourth interior angles; the imaginary quadrangle has a first side, a second side, a third side and a fourth side associated with the first abutment wall, the second abutment wall, the third abutment wall and the fourth abutment wall, respectively, a first interior angle is formed between the first side and the second side, a second interior angle is formed between the second side and the third side, a third interior angle is formed between the third side and the fourth side, and a fourth interior angle is formed between the fourth side and the first side; The first interior angle and the third interior angle are equal to one another, and the second interior angle and the fourth interior angle are unequal to one another.

[0011] The present invention also provides a rotary cutting tool rotatable in a rotational direction about a tool axis, the rotary cutting tool comprising a tool body having a first insert receiving pocket and a second insert receiving pocket, and a cutting insert of the type described above, the cutting insert being removably secured within each of the first insert receiving pocket and the second insert receiving pocket.

[0012] For a better understanding, the invention will now be described, purely by way of example, with reference to the accompanying drawings, in which dashed chain lines represent cutting boundaries of partial views of elements, in which: [Brief description of the drawings]

[0013] [Figure 1] 1 is a top perspective view of a cutting insert according to some embodiments of the present invention. [Diagram 2] FIG. 2 is a bottom perspective view of the cutting insert shown in FIG. 1. [Diagram 3] FIG. 2 is a top view of the cutting insert shown in FIG. [Figure 4] FIG. 2 is a bottom view of the cutting insert shown in FIG. [Diagram 5] FIG. 2 is a side view of the cutting insert shown in FIG. [Figure 6] 6 is a cross-sectional view of the cutting insert shown in FIG. 5 taken along line VI-VI. [Figure 7] 1 is a side view of a tool body according to some embodiments of the present invention. FIG. [Figure 8] 8 is a top view of a first insert-receiving pocket of the tool body shown in FIG. 7. FIG. [Figure 9] FIG. 8 is a top view of a second insert-receiving pocket of the tool body shown in FIG. 7. [Figure 10] 1 is a perspective view of a cutting tool according to some embodiments of the present invention. [Figure 11] FIG. 11 is a first side view of the cutting insert shown in FIG. [Figure 12] FIG. 11 is a second side view of the cutting insert shown in FIG. [Figure 13] FIG. 11 is an end view of the cutting tool shown in FIG. [Figure 14] 11 is a cross-sectional view of the cutting insert shown in FIG. 10 in relation to a first insert-receiving pocket. [Figure 15] FIG. 15 is a cross-sectional view of the cutting insert shown in FIG. 14 taken along line XV-XV. [Figure 16] 11 is a cross-sectional view of the cutting tool shown in FIG. 10 in relation to a second insert-receiving pocket. [Figure 17] FIG. 17 is a cross-sectional view of the cutting tool shown in FIG. 16 taken along line XVII-XVII. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] As shown in Figures 1-6, one aspect of the present invention relates to a cutting insert 20 having opposing upper and lower sides 22, 24 interconnected by a peripheral side 26, and an insert axis A1 passing through the upper and lower sides 22, 24 (or more precisely, passing through a plane defined by the upper and lower sides).

[0015] In some embodiments of the present invention, the lower surface 24 may be flat.

[0016] Additionally, in some embodiments of the present invention, the through hole 28 may extend along the insert axis A1.

[0017] Furthermore, in some embodiments of the present invention, the cutting insert 20 is preferably manufactured by die pressing and sintering of a hard metal such as tungsten carbide, and may be coated or uncoated.

[0018] As shown in FIGS. 1 and 3, the upper surface 22 may include a flat upper central region 27.

[0019] In some embodiments of the present invention, the through-holes 28 may intersect the upper central region 27 .

[0020] As shown in Figures 1 and 3, a continuous upper peripheral edge 30 is formed at the intersection of upper surface 22 and peripheral side surface 26, and upper peripheral edge 30 has a first upper cutting edge 32 and a second upper cutting edge 34.

[0021] In some embodiments of the present invention, the upper periphery 30 does not exhibit rotational symmetry about the insert axis A1.

[0022] Also, in some embodiments of the present invention, the first upper cutting edge 32 and the second upper cutting edge 34 may not be identical.

[0023] Additionally, in some embodiments of the present invention, the first upper cutting edge 32 and the second upper cutting edge 34 may be spaced apart by opposing first nose edges 33,35.

[0024] As shown in Figures 1 and 3, the first upper cutting edge 32 can include a first major cutting edge portion 36a and a first minor cutting edge portion 36b, and the second upper cutting edge 34 can include a second major cutting edge 38a and a second minor cutting edge 38b.

[0025] In some embodiments of the present invention, in a top view of the cutting insert 20, as shown in FIG. 3, each of the first major cutting edge portion 36a and the second major cutting edge portion 38a may have an outward convex shape, and each of the first minor cutting edge portion 36b and the second minor cutting edge portion 38b may be straight.

[0026] Also, in some embodiments of the present invention, in a side view of the cutting insert 20, as shown in FIG. 5, the first main cutting edge portion 36a and the second main cutting edge portion 38a may have an upward convex shape.

[0027] As shown in Figures 1 and 3, the first nose edge 33 can extend between the first major cutting edge portion 36a and the second minor cutting edge portion 38b, and the second nose edge 35 can extend between the second major cutting edge portion 38a and the first minor cutting edge portion 36b.

[0028] As shown in Figures 2, 4 and 5, the lower central ridge 40 extends downwardly from the lower surface 24 and away from the upper surface 22, and the lower central ridge 40 includes a first abutment wall 42a, a second abutment wall 42b, a third abutment wall 42c and a fourth abutment wall 42d that traverse the lower surface 24.

[0029] The first abutment wall 42 a , the second abutment wall 42 b , the third abutment wall 42 c and the fourth abutment wall 42 d are disposed successively on an envelope surface 43 that extends around the periphery of the lower central ridge 40 .

[0030] In some embodiments of the present invention, lower central ridge 40 may have a bottom surface 44 and envelope surface 43 may extend from underside 24 of bottom surface 44 .

[0031] Additionally, in some embodiments of the present invention, the through holes 28 may intersect the bottom surface 44 .

[0032] As shown in FIG. 2, a continuous lower peripheral edge 46 is formed at the intersection of lower surface 24 and peripheral side surface 26 .

[0033] In some embodiments of the present invention, the lower peripheral edge 46 may be free of cutting edges.

[0034] In some embodiments, because of the lower central ridge 40, the cutting insert 20 is single-sided (or non-reversible), that is, the cutting edge cannot be replaced by flipping it over.

[0035] As shown in FIG. 4 , in a bottom view of the cutting insert 20 , each of the first abutment wall 42 a , the second abutment wall 42 b , the third abutment wall 42 c and the fourth abutment wall 42 d may be located inside the lower outer periphery 46 .

[0036] In some embodiments of the present invention, in a bottom view of the cutting insert 20 , the entire lower central ridge 40 may be located inside the lower peripheral edge 46 .

[0037] By having the first abutment wall 42a, the second abutment wall 42b, the third abutment wall 42c and the fourth abutment wall 42d, the lower central ridge 40 can be used to removably secure the cutting insert 20 to radial and axial support surfaces of a cutting tool.

[0038] It should be appreciated that the insert's outer peripheral side 26 may thus be completely spaced from the surface of the cutting tool, thereby optimizing the shape of the first upper cutting edge 32 and the second upper cutting edge 34, as well as the portion of the outer peripheral side 26 that provides clearance for the first cutting edge 32 and the second cutting edge 34, without any shape constraints associated with removably securing the cutting insert 20 to the cutting tool.

[0039] As shown in Figure 6, in a cross section taken on a first horizontal plane PH1 perpendicular to the insert axis A1 and intersecting the envelope surface 43, the first abutment wall 42a, the second abutment wall 42b, the third abutment wall 42c and the fourth abutment wall 42d define an imaginary rectangle QI, and the imaginary rectangle QI has a first interior angle α1 and a third interior angle α3 that are diagonally opposite, and a second interior angle α2 and a fourth interior angle α4 that are diagonally opposite.

[0040] Also, as shown in FIG. 6, the imaginary rectangle QI has a first side S1, a second side S2, a third side S3 and a fourth side S4 associated with the first abutment wall 42a, the second abutment wall 42b, the third abutment wall 42c and the fourth abutment wall 42d, respectively, and a first interior angle α1 is formed between the first side S1 and the second side S2, a second interior angle α2 is formed between the second side S2 and the third side S3, a third interior angle α3 is formed between the third side S3 and the fourth side S4, and a fourth interior angle α4 is formed between the fourth side S4 and the first side S1.

[0041] In some embodiments of the present invention, in a cross section taken in the first horizontal plane PH1, each of the first abutment wall 42a, the second abutment wall 42b, the third abutment wall 42c and the fourth abutment wall 42d may be straight.

[0042] Additionally, in some embodiments of the present invention, each of the first abutment wall 42a, the second abutment wall 42b, the third abutment wall 42c and the fourth abutment wall 42d may be flat.

[0043] Furthermore, in some embodiments of the present invention, each of the first abutment wall 42a, the second abutment wall 42b, the third abutment wall 42c and the fourth abutment wall 42d may be parallel to the insert axis A1.

[0044] As shown in Figures 2 and 4, the envelope surface 43 may have a first corner surface 45a, a second corner surface 45b, a third corner surface 45c, and a fourth corner surface 45d, where the first corner surface 45a is disposed between the first abutment wall 42a and the second abutment wall 42b, the second corner surface 45b is disposed between the second abutment wall 42b and the third abutment wall 42c, the third corner surface 45c is disposed between the third abutment wall 42c and the fourth abutment wall 42d, and the fourth corner surface 45d is disposed between the fourth abutment wall 42d and the first abutment wall 42a.

[0045] As shown in FIG. 6, in a cross section taken on a first horizontal plane PH1, the first corner surface 45a may be concave, the second corner surface 45b and the third corner surface 45c may be straight, and the fourth corner surface 45d may be convex.

[0046] In some embodiments of the present invention, in a cross section taken on the first horizontal plane PH1, the first corner surface 45a, the second corner surface 45b, the third corner surface 45c and the fourth corner surface 45d may be located inside the imaginary quadrilateral QI.

[0047] As shown in FIG. 4, the first abutment wall 42a may include two spaced apart first sub-walls 42a' and 42a'', and the third abutment wall 42c may include two spaced apart third sub-walls 42c' and 42c''.

[0048] In some embodiments of the present invention, as shown in FIG. 6, in a cross section taken on the first horizontal plane PH1, the two first sub-walls 42a', 42a'' may be collinear, and the two third sub-walls 42c', 42c'' may be collinear.

[0049] As shown in Figures 4 and 6, the two first sub-walls 42a', 42a'' may be spaced apart by a first protrusion 47a, and the two third sub-walls 42c', 42c'' may be spaced apart by a third protrusion 47c.

[0050] In some embodiments of the present invention, in a cross section taken on the first horizontal plane PH1, the first protrusion 47a and the third protrusion 47c may be located outside the imaginary quadrangle QI.

[0051] Also, in some embodiments of the present invention, a first radial plane PR1 including the insert axis A1 and perpendicular to the first side S1 may intersect the first protrusion 47a, and a third radial plane PR3 including the insert axis A1 and perpendicular to the third side S3 may intersect the third protrusion 47c.

[0052] As shown in FIG. 6, in a cross section taken on the first horizontal plane PH1, the through-hole 28 can be located entirely inside the imaginary rectangle QI.

[0053] It should be appreciated that in an embodiment of the present invention in which the through hole 28 extends along the insert axis A1 and is located completely inside the imaginary rectangle QI, the first protrusion 47a and the third protrusion 47c advantageously provide a lower central ridge 40 with an increased minimum wall thickness adjacent the through hole 28, thus increasing the strength of the cutting insert 20.

[0054] According to the present invention, the first interior angle α1 and the third interior angle α3 are equal to each other, and the second interior angle α2 and the fourth interior angle α4 are not equal to each other. Therefore, the imaginary quadrilateral QI may be described as an irregular quadrilateral.

[0055] In some embodiments of the present invention, both the second interior angle α2 and the fourth interior angle a4 may be different from the first interior angle α1 and the third interior angle α3.

[0056] Also, in some embodiments of the present invention, the second interior angle α2 may be an acute angle and the fourth interior angle α4 may be an obtuse angle.

[0057] As shown in FIG. 6, in a cross section taken on the first horizontal plane PH1, the sum of the second interior angle α2 and the fourth interior angle α4 may be twice the value of either the first interior angle α1 or the third interior angle α3.

[0058] Thus, in some embodiments of the present invention, both the first interior angle α1 and the third interior angle α3 may be right angles.

[0059] Because the diagonally opposed second interior angle α2 and fourth interior angle α4 are not equal to one another, the imaginary quadrilateral QI does not have rotational symmetry about the insert axis A1 (at any angle less than 360°). In such a case, the cutting insert 20 as a whole is not rotationally symmetric even when the first upper cutting edge 32 and the second upper cutting edge 34 are rotationally symmetric about the insert axis A1 (at an angle less than 360°).

[0060] As shown in FIG. 6, the imaginary quadrangle QI has a first corner point NC1, a second corner point NC2, a third corner point NC3, and a fourth corner point NC4, which are associated with a first interior angle α1, a second interior angle α2, a third interior angle α3, and a fourth interior angle α4, respectively.

[0061] In some embodiments of the present invention, the first corner point NC1 and the third corner point NC3 may be located at a first distance d1 and a third distance d3, respectively, from the insert axis A1, and the first distance d1 and the third distance d3 may be equal to each other.

[0062] As shown in FIG. 6, in a cross section taken in the first horizontal plane PH1, the first corner point NC1, the second corner surface NC2, the third corner surface NC3 and the fourth corner surface NC4 may be located outside the lower central ridge 40.

[0063] In some embodiments of the present invention, in a cross section taken in the first horizontal plane PH1, at least one of the first corner point NC1 and the third corner point NC3 may be located outside the lower outer periphery 46.

[0064] As shown in FIG. 6, each of the first side S1 and the third side S3 may be longer than each of the second side S2 and the fourth side S4.

[0065] In some embodiments of the present invention, the first side S1 and the third side S3 may be non-parallel, and the second side S2 and the fourth side S4 may be non-parallel.

[0066] As shown in Figures 3 and 6, a first vertical plane PV1 including a first side S1 may intersect the first main cutting edge portion 36a and the second main cutting edge portion 38a, and a third vertical plane PV3 including a third side S3 may intersect the first main cutting edge portion 36a and the second main cutting edge portion 38a.

[0067] Also, as shown in Figures 3 and 6, a second vertical plane PV2 including the second side S2 may intersect the second main cutting edge portion 38a and the first minor cutting edge portion 36b, and a fourth vertical plane PV4 including the fourth side S4 may intersect the first main cutting edge portion 36a and the second minor cutting edge portion 38b.

[0068] Further, as shown in FIG. 3, the first nose edge 33 may be located entirely within one of the four spatial regions defined by the intersection of the first vertical plane PV1 and the fourth vertical plane PV4, and the second nose edge 35 may be located entirely within one of the four spatial regions defined by the intersection of the second vertical plane PV2 and the third vertical plane PV3.

[0069] In some embodiments of the present invention, the first vertical plane PV1, the second vertical plane PV2, the third vertical plane PV3 and the fourth vertical plane PV4 may be parallel to the insert axis A1.

[0070] As shown in Figures 7-13, another aspect of the present invention relates to a rotary cutting tool 48 rotatable about a tool axis AT in a rotational direction RT.

[0071] The rotary cutting tool 48 comprises a tool body 50 having a first insert receiving pocket 52 and a second insert receiving pocket 54, and one of the cutting inserts 20 described above removably secured within each of the first insert receiving pocket 52 and the second insert receiving pocket 54.

[0072] In some embodiments of the present invention, the tool body 50 may have an outer peripheral surface 56 interrupted by a first notch 58 and a second notch 60, and the first insert receiving pocket 52 and the second insert receiving pocket 54 may be formed within the first notch 58 and the second notch 60, respectively.

[0073] Additionally, in some embodiments of the present invention, the first notch 58 and the second notch 60 may be formed in the axial forward end 61 of the tool body 50 .

[0074] Additionally, in some embodiments of the present invention, the first notch 58 and the second notch 60 may communicate with one another.

[0075] Still further, in some embodiments of the present invention, the first notch 58 and the second notch 60 may include a first tip groove 62 and a second tip groove 64, respectively.

[0076] As shown in FIG. 7, the first insert receiving pocket 52 and the second insert receiving pocket 54 may have first and second seating surfaces 66 and 68, respectively, that face in the rotational direction RT.

[0077] It will be appreciated that FIG. 7 shows second insert-receiving pocket 54 and its associated features with details hidden.

[0078] In some embodiments of the present invention, the first bearing surface 66 and the second bearing surface 68 may intersect the circumferential outer surface 56 .

[0079] Additionally, in some embodiments of the present invention, each of the first and second bearing surfaces 66, 68 may be flat.

[0080] As shown in FIG. 12, in a side view of the cutting tool 48, the second bearing surface 68 may be inclined at an acute inclination angle β1 relative to the tool axis AT such that an axially rear portion of the second bearing surface is arranged to rotate prior to an axially front portion of the second bearing surface.

[0081] In some embodiments of the present invention, the first seating surface 66 may also be inclined relative to the tool axis AT such that an axially rear portion of the first seating surface is arranged to rotate prior to an axially front portion of the first seating surface.

[0082] As shown in Figures 12 and 13, the lower side 24 of the first cutting insert of the two cutting inserts 20' can face the first seating surface 66, and the lower side 24 of the second cutting insert of the two cutting inserts 20'' can face the second seating surface 68.

[0083] In some embodiments of the present invention, the underside 24 of the first cutting insert 20 ′ may contact the first seating surface 66 and the underside 24 of the second cutting insert 20 ″ may contact the second seating surface 68 .

[0084] As shown in FIGS. 10-13, the first upper cutting edge 32 of the first cutting insert 20' may be active and the second upper cutting edge 34 of the second cutting insert 20'' may be active.

[0085] In some embodiments of the present invention, the first nose edge 33 and the second nose edge 35 may not be configured to perform a cutting action, and therefore the first nose edge 33 of the first cutting insert 20' and the second nose edge 35 of the second cutting insert 20'' do not engage a workpiece (not shown).

[0086] In some embodiments of the present invention, the rotary cutting tool 48 may be used for milling operations.

[0087] Additionally, in some embodiments of the present invention, the rotary cutting tool 48 may be in the form of a ballnose end mill for use in profiling and profiling operations.

[0088] It should be appreciated that in some embodiments of the present invention, a substantial portion of the effective second upper cutting edge 34 of the second cutting insert 20'' may be rotationally aligned with the effective first upper cutting edge 32 of the first cutting insert 20' about the tool axis AT.

[0089] As shown in FIG. 13, the first upper cutting edge 32 of the first cutting insert 20' may intersect the tool axis AT.

[0090] It should be appreciated that for embodiments of the present invention in which the effective first upper cutting edge 32 of the first cutting insert 20' intersects the tool axis AT, the cutting tool 48 may advantageously perform the cutting action by advancing axially along the tool axis AT without leaving an uncut "midfoot" in the workpiece (not shown) that would require further cutting actions to remove and may inadvertently cause damage to the cutting edge.

[0091] It should be appreciated that for improved visual clarity, FIGS. 10-12 show the tool axis AT unobstructed by the tool body 50. As shown in FIG.

[0092] As shown in Figures 7-9, first insert receiving pocket 52 and second insert receiving pocket 54 may include a first recess 70 and a second recess 72 in first seating surface 66 and second seating surface 68, respectively.

[0093] In some embodiments of the present invention, the first recess 70 and the second recess 72 do not intersect the outer periphery 56 .

[0094] Also, in some embodiments of the present invention, the first recess 70 may be circumferentially surrounded by the first seating surface 66 and the second recess 72 may be circumferentially surrounded by the second seating surface 68 .

[0095] Further, in some embodiments of the present invention, the lower central ridge 40 of the first cutting insert 20' may occupy the first recess 70 and the lower central ridge 40 of the second cutting insert 20'' may occupy the second recess 72.

[0096] As shown in Figures 7-9, the first recess 70 can include a first spaced apart radial support surface 74 and a first axial support surface 76, and the second recess 72 can include a second spaced apart radial support surface 78 and a second axial support surface 80.

[0097] In some embodiments of the present invention, as shown in Figures 14 and 16, the first abutment wall 42a and the second abutment wall 42b of the first cutting insert 20' may contact the first radial support surface 74 and the first axial support surface 76, respectively, and the third abutment wall 42c and the fourth abutment wall 42d of the second cutting insert 20'' may contact the second radial support surface 78 and the second axial support surface 80, respectively.

[0098] It should be understood that Figures 14 and 16 are detailed cross-sectional views of cutting tool 48 taken parallel to first and second seating surfaces 66, 68 of first and second insert receiving pockets 52, 54, respectively.

[0099] It should be understood that because the first interior angle α1 is associated with the first abutment wall 42a and the second abutment wall 42b, and the third interior angle α3 is associated with the third abutment wall 42c and the fourth abutment wall 42d, and the first interior angle α1 and the third interior angle α3 are equal, the first radial support surface 74 and the first axial support surface 76 of the first recess 70 can have a configuration corresponding to the second radial support surface 78 and the second axial support surface 80 of the second recess 72, such that the first cutting insert 20' and the second cutting insert 20'' can be removably secured within the respective first insert receiving pocket 52 and second insert receiving pocket 54 with a correspondingly high level of stability.

[0100] In some embodiments of the present invention, the lower central ridge 40 of the first cutting insert 20' may occupy only the first recess 70 in a single assembly position, in which the first abutment wall 42a and the second abutment wall 42b face the first radial support surface 74 and the first axial support surface 76, respectively, and the lower central ridge 40 of the second cutting insert 20'' may occupy only the second recess 72 in a single assembly position, in which the third abutment wall 42c and the fourth abutment wall 42d face the second radial support surface 78 and the second axial support surface 80, respectively.

[0101] With such an embodiment of the invention, it should be appreciated that if the active first upper cutting edge 32 of the first cutting insert 20' becomes worn or used, the first cutting insert 20' cannot be inadvertently "reset" into the first recess 70 of the first insert receiving pocket 52. Similarly, it should be appreciated that if the active second upper cutting edge 34 of the second cutting insert 20" becomes worn or used, the second cutting insert 20" cannot be inadvertently "reset" into the second recess 72 of the second insert receiving pocket 54. Such a "fool-proof" arrangement prevents incorrect assembly of the cutting tool 48.

[0102] It should be understood that the use of the term “replacement” in the previous paragraph refers to the attempted removal, rotation of approximately 180° about the insert axis A1, and replacement of the first insert 20′ and second insert 20″ within the respective first insert receiving pocket 52 and second insert receiving pocket 54.

[0103] The cutting insert 20 cannot be indexed and replaced in the same insert-receiving pocket 52, 54, but can be placed in the other insert-receiving pocket 54, 52. In other words, when the active upper cutting edges 32, 34 of a pair of inserts used in the same tool body become worn, the inserts can be switched out. This allows the same insert to be used in both insert pockets, with the insert in each pocket having a different active cutting edge. The upper cutting edges 32, 34 may be numbered and / or equipped with a wear indicator to help the operator keep track of which cutting edges have already been used.

[0104] As shown in FIGS. 7-9, at least a portion of the first radial support surface 74 and at least a portion of the second radial support surface 78 may be rotationally coincident about the tool axis AT.

[0105] In some embodiments of the present invention, the aforementioned portions of the first radial support surface 74 and the aforementioned portions of the second radial support surface 78 may exhibit two-fold rotational symmetry about the tool axis AT.

[0106] As shown in FIGS. 7-9, at least a portion of the first axial bearing surface 76 and at least a portion of the second axial bearing surface 80 may be rotationally coincident about the tool axis AT.

[0107] In some embodiments of the present invention, the aforementioned portions of the first axial bearing surface 76 and the aforementioned portions of the second axial bearing surface 80 may exhibit two-fold rotational symmetry about the tool axis AT.

[0108] For embodiments of the present invention in which at least a portion of the first radial support surface 74 and at least a portion of the second radial support surface 78 are rotationally aligned about the tool axis AT, and at least a portion of the first axial support surface 76 and at least a portion of the second axial support surface 80 are rotationally aligned about the tool axis AT, it should be understood that the first recess 70 and the second recess 72 in the first insert receiving pocket 52 and the second insert receiving pocket 54 can provide equivalent levels of radial and axial support for the first cutting insert 20' and the second cutting insert 20''.

[0109] It should also be appreciated that for embodiments of the present invention in which at least a portion of the first radial support surface 74 and at least a portion of the second radial support surface 78 are rotationally coincident about the tool axis AT, and at least a portion of the first axial support surface 76 and at least a portion of the second axial support surface 80 are rotationally coincident about the tool axis AT, an alternative cutting tool assembly may be constructed in which two identical cutting inserts having two-fold rotational symmetry, as described in the above-referenced US 6,536,996, are removably secured within the first insert receiving pocket 52 and the second insert receiving pocket 54 of the tool body 50.

[0110] As shown in Figures 7 and 9, the first recess 70 can include a first radial stop wall 82 facing the first radial support surface 74, and the second recess 72 can include a second radial stop wall 84 facing the second radial support surface 78.

[0111] In some embodiments of the present invention, the third abutment wall 42c and the fourth abutment wall 42d of the first cutting insert 20' do not contact the first recess 70, and the first abutment wall 42a and the second abutment wall 42b of the second cutting insert 20'' do not contact the second recess 72.

[0112] Therefore, it should be appreciated that in some embodiments of the present invention, as shown in Figures 15 and 17, the first radial stop wall 82 may be spaced apart from the third abutment wall 42c of the first cutting insert 20', and the second radial stop wall 84 may be spaced apart from the first abutment wall 42a of the second cutting insert 20''.

[0113] For an embodiment of the present invention in which the first radial stop wall 82 is spaced from the third abutment wall 42c of the first cutting insert 20' and the second radial stop wall 84 is spaced from the first abutment wall 42a of the second cutting insert 20'', it should be understood that the presence and position of the first radial stop wall 82 in the first recess 70 physically prevents inadvertent "resetting" of the first cutting insert 20' in the first recess 70, and the presence and position of the second radial stop wall 84 in the second recess 72 physically prevents inadvertent "resetting" of the second cutting insert 20'' in the second recess 72.

[0114] It should also be understood that the presence and position of the first radial stop wall 82 within the first recess 70 physically prevents any cutting insert 20 from being assembled into the first recess 70 and oriented such that the second upper cutting edge 34 is effective, and that the presence and position of the second radial stop wall 84 within the second recess 72 physically prevents any cutting insert 20 from being assembled into the second recess 72 and oriented such that the first upper cutting edge 32 is effective.

[0115] In some embodiments of the present invention, there are no other surfaces of the envelope surface 43 of the first cutting insert that may contact the first recess 70, other than the first abutment wall 42a and the second abutment wall 42b of the first cutting insert 20' contacting the first radial support surface 74 and the first axial support surface 76, respectively, and there are no other surfaces of the envelope surface 43 of the second cutting insert that may contact the second recess 72, other than the third abutment wall 42c and the fourth abutment wall 42d of the second cutting insert 20'' contacting the second radial support surface 78 and the second axial support surface 80, respectively.

[0116] As shown in Figures 8 and 9, the first recess 70 can include a first floor 86 having a first female thread 88 therein, and the second recess 72 can include a second floor 90 having a second female thread 92 therein.

[0117] As shown in Figures 15 and 17, the bottom surface 44 of the lower central ridge 40 of the first cutting insert 20' can be spaced from the first floor surface 86, and the bottom surface 44 of the lower central ridge 40 of the second cutting insert 20'' can be spaced from the second floor surface 90.

[0118] In some embodiments of the present invention, a first clamping screw 94' may extend through the through hole 28 of the first cutting insert 20' and engage the first female threads 88, and a second clamping screw 94'' may extend through the through hole 28 of the second cutting insert 20' and engage the second female threads 92.

[0119] It should be appreciated that the first fastening screw 94' and the second fastening screw 94'' may be identical.

[0120] Also, in some embodiments of the present invention, the first female threads 88 may extend along a first female thread axis B1 and the insert axis A1 of the first cutting insert 20' may be non-coaxial with the first female thread axis B1, and the second female threads 92 may extend along a second female thread axis B2 and the insert axis A1 of the second cutting insert 20'' may be non-coaxial with the second female thread axis B2.

[0121] In such an embodiment of the present invention, the through bore 28 of the first cutting insert 20 ′ may be eccentric with respect to the first female threads 88 and the through bore 28 of the second cutting insert 20 ″ may be eccentric with respect to the second female threads 92 .

[0122] It should be appreciated that the eccentric relationship between the through hole 28 and the first female thread 88 of the first cutting insert 20' promotes contact between the first abutment wall 42a and the second abutment wall 42b of the first cutting insert 20' and the first radial support surface 74 and the first axial support surface 76, respectively, when the first clamping screw 94' is tightened.

[0123] It should also be appreciated that the eccentric relationship between the through hole 28 of the second cutting insert 20'' and the second female thread 92 promotes contact between the third abutment wall 42c and the fourth abutment wall 42d of the second cutting insert 20'' and the second radial support surface 78 and the second axial support surface 80, respectively, when the second clamping screw 94'' is tightened.

[0124] Although the invention has been described in some detail, it should be understood that various changes and modifications can be made without departing from the spirit and scope of the invention as hereinafter claimed.

Claims

1. A single-sided cutting insert (20), comprising: an insert axis (A1) passing through said upper and lower opposing sides (22, 24) interconnected by a peripheral side (26); an upper peripheral edge (30) at a line of intersection of the upper side surface (22) and the peripheral side surface (26), the upper peripheral edge (30) having a first upper cutting edge (32) and a second upper cutting edge (34); a lower central ridge (40) extending downwardly from said lower surface (24) and away from said upper surface (22); the lower central ridge (40) includes a first abutment wall (42a), a second abutment wall (42b), a third abutment wall (42c) and a fourth abutment wall (42d) in a transverse direction on the lower side surface (24), the first abutment wall (42a), the second abutment wall (42b), the third abutment wall (42c) and the fourth abutment wall (42d) being continuously arranged on an envelope surface (43) extending around the periphery of the lower central ridge (40); In a cross section taken on a first horizontal plane (PH1) perpendicular to the insert axis (A1) and intersecting the envelope surface (43), the first abutment wall (42a), the second abutment wall (42b), the third abutment wall (42c), and the fourth abutment wall (42d) define a virtual quadrangle (QI) surrounded by lines obtained by virtually extending each of the sides appearing in the cross section in both directions, and the virtual quadrangle (QI) has a first interior angle (α1) and a third interior angle (α3) that are diagonally opposed to each other, and a second interior angle (α2) and a fourth interior angle (α4) that are diagonally opposed to each other, The virtual quadrangle (QI) has a first side (S1), a second side (S2), a third side (S3), and a fourth side (S4) including the respective sides of the first abutment wall (42a), the second abutment wall (42b), the third abutment wall (42c), and the fourth abutment wall (42d), the first interior angle (α1) is formed between the first side (S1) and the second side (S2), the second interior angle (α2) is formed between the second side (S2) and the third side (S3), the third interior angle (α3) is formed between the third side (S3) and the fourth side (S4), and the fourth interior angle (α4) is formed between the fourth side (S4) and the first side (S1), A single-sided cutting insert (20), wherein the first interior angle (α1) and the third interior angle (α3) are equal to each other, and the second interior angle (α2) and the fourth interior angle (α4) are not equal to each other.

2. The cutting insert (20) according to claim 1, wherein the upper outer peripheral edge portion (30) has no portion that is rotationally symmetric about the insert axis (A1).

3. The cutting insert (20) of claim 1, wherein the first upper cutting edge (32) and the second upper cutting edge (34) are not identically shaped.

4. 2. The cutting insert (20) according to claim 1, wherein in a cross section taken on the first horizontal plane (PH1), each of the first abutment wall (42a), the second abutment wall (42b), the third abutment wall (42c) and the fourth abutment wall (42d) is straight.

5. The cutting insert (20) according to claim 1, wherein the through hole (28) extends along the insert axis (A1).

6. The cutting insert (20) according to claim 5, wherein in a cross section taken on the first horizontal plane (PH1), the through hole (28) is located completely inside the imaginary quadrangle (QI).

7. The cutting insert (20) according to claim 1, wherein the second interior angle (α2) is an acute angle and the fourth interior angle (α4) is an obtuse angle.

8. The cutting insert (20) according to claim 1, wherein both the first interior angle (α1) and the third interior angle (α3) are right angles.

9. A lower outer peripheral edge portion (46) is formed at the intersection line between the lower surface (24) and the outer peripheral side surface (26), 2. The cutting insert (20) according to claim 1, wherein in a bottom view of the cutting insert (20), each of the first abutment wall (42a), the second abutment wall (42b), the third abutment wall (42c) and the fourth abutment wall (42d) is located inside the lower outer circumferential edge portion (46).

10. The cutting insert (20) according to claim 1, wherein each of the first side (S1) and the third side (S3) is longer than each of the second side (S2) and the fourth side (S4).

11. The first upper cutting edge (32) includes a first major cutting edge portion (36a) and a first minor cutting edge portion (36b); The second upper cutting edge (34) includes a second major cutting edge (38a) and a second minor cutting edge (38b); In a top view of the cutting insert (20), Each of the first main cutting edge portion (36a) and the second main cutting edge portion (38a) has an outward convex shape, The cutting insert (20) of claim 1, wherein each of the first minor cutting edge portion (36b) and the second minor cutting edge portion (38b) is straight.

12. a first vertical plane (PV1) including the first side (S1) intersects the first main cutting edge portion (36a) and the second main cutting edge portion (38a); The cutting insert (20) according to claim 11, wherein a third vertical plane (PV3) including the third side (S3) intersects the first main cutting edge portion (36a) and the second main cutting edge portion (38a).

13. a second vertical plane (PV2) including the second side (S2) intersects the second major cutting edge portion (38a) and the first minor cutting edge portion (36b); The cutting insert (20) according to claim 11, wherein a fourth vertical plane (PV4) including the fourth side (S4) intersects the first major cutting edge portion (36a) and the second minor cutting edge portion (38b).

14. A rotary cutting tool (48) rotatable about a tool axis (AT) in a rotational direction (RT), a tool body (50) having a first insert-receiving pocket (52) and a second insert-receiving pocket (54); 2. The cutting insert (20) of claim 1 removably secured within each of said first insert receiving pocket (52) and said second insert receiving pocket (54); A rotary cutting tool (48) comprising:

15. the first insert receiving pocket (52) and the second insert receiving pocket (54) have first and second bearing surfaces (66) and (68), respectively, facing in the rotational direction (RT); 15. The rotary cutting tool (48) of claim 14, wherein the lower side (24) of a first cutting insert (20') of the two cutting inserts faces the first seating surface (66) and the lower side (24) of a second cutting insert (20'') of the two cutting inserts faces the second seating surface (68).

16. the first upper cutting edge (32) of the first cutting insert (20') functions as a cutting edge; The rotary cutting tool (48) of claim 15, wherein the second upper cutting edge (34) of the second cutting insert (20'') functions as a cutting edge.

17. The rotary cutting tool (48) of claim 16, wherein the first upper cutting edge (32) of the first cutting insert (20') intersects the tool axis (AT).

18. the first insert receiving pocket (52) and the second insert receiving pocket (54) including a first recess (70) and a second recess (72) in the first seating surface (66) and the second seating surface (68), respectively; the lower central ridge (40) of the first cutting insert (20') occupies the first recess (70); The rotary cutting tool (48) of claim 15, wherein the lower central ridge (40) of the second cutting insert (20'') occupies the second recess (72).

19. the first recess (70) includes a first spaced apart radial support surface (74) and a first spaced apart axial support surface (76), and the second recess (72) includes a second spaced apart radial support surface (78) and a second spaced apart axial support surface (80); 20. The rotary cutting tool (48) of claim 18, wherein the first abutment wall (42a) and the second abutment wall (42b) of the first cutting insert (20') contact the first radial support surface (74) and the first axial support surface (76), respectively, and the third abutment wall (42c) and the fourth abutment wall (42d) of the second cutting insert (20'') contact the second radial support surface (74) and the second axial support surface (76), respectively.

20. 20. The rotary cutting tool (48) of claim 19, wherein at least a portion of the first radial support surface (74) and at least a portion of the second radial support surface (78) have coincident rotational trajectories about the tool axis (AT).

21. 20. The rotary cutting tool (48) of claim 19, wherein at least a portion of the first axial bearing surface (76) and at least a portion of the second axial bearing surface (80) have coincident rotational loci about the tool axis (AT).

22. the third abutment wall (42c) and the fourth abutment wall (42d) of the first cutting insert (20') do not contact the first recess (70); 20. The rotary cutting tool (48) of claim 19, wherein the first abutment wall (42a) and the second abutment wall (42b) of the second cutting insert (20'') do not contact the second recess (72).

23. the lower central ridge (40) of the first cutting insert (20') may occupy only the first recess (70) in a single assembly position, in which the first abutment wall (42a) and the second abutment wall (42b) face the first radial support surface (74) and the first axial support surface (76), respectively; 20. The rotary cutting tool (48) of claim 19, wherein the lower central ridge (40) of the second cutting insert (20'') can occupy only the second recess (72) in a single assembly position, in which the third abutment wall (42c) and the fourth abutment wall (42d) face the second radial support surface (78) and the second axial support surface (80), respectively.

24. A single-sided cutting insert (20), comprising: an insert axis (A1) passing through said upper and lower opposing sides (22, 24) interconnected by a peripheral side (26); A through hole (28) extending along the insert axis (A1) and connecting the upper surface (22) and the lower surface (24); an upper outer peripheral edge (30) at the intersection of the upper side (22) and the outer peripheral side (26), the upper outer peripheral edge (30) having first and second upper cutting edges (32) and (34) spaced apart from each other by opposing first and second nose edges (33) and (35); a lower central ridge (40) extending downwardly from said lower surface (24) and away from said upper surface (22); the lower central ridge (40) has an envelope surface (43) extending around the periphery of the lower central ridge (40) and includes a first abutment wall (42a), a second abutment wall (42b), a third abutment wall (42c) and a fourth abutment wall (42d) arranged successively across the lower surface (24); In a cross section taken on a first horizontal plane (PH1) perpendicular to the insert axis (A1) and intersecting the envelope surface (43), the first abutment wall (42a), the second abutment wall (42b), the third abutment wall (42c), and the fourth abutment wall (42d) define a virtual quadrangle (QI) surrounded by respective sides appearing in the cross section, and the virtual quadrangle (QI) passes through the insert axis (A1), The virtual quadrangle (QI) is not rotationally symmetric about the insert axis (A1), The first upper cutting edge (32) and the second upper cutting edge (34) are not rotationally symmetrical about the insert axis (A1), A single-sided cutting insert (20), wherein in a cross section taken on the first horizontal plane (PH1), the through hole (28) is located completely inside the imaginary quadrangle (QI).

25. The virtual quadrilateral (QI) is a first interior angle (α1) and a third interior angle (α3) that are diagonally opposite and equal to each other; A second interior angle (α2) and a fourth interior angle (α4) that are diagonally opposite and unequal to each other; and wherein the second interior angle (α2) and the fourth interior angle (α4) are not equal to both the first interior angle (α1) and the third interior angle (α3).

Images