Patent Description:
Within the field of rotary cutting tools used in slotting operations, there are many examples of disk-shaped cutting bodies having a plurality of insert receiving pockets and a plurality of cutting inserts removably retained therein.

<CIT> discloses a slotting cutter having a disk-shaped cutting body with a plurality of identical insert receiving pockets and an equal number of identical non-indexable cutting inserts removably retained therein.

<CIT> discloses a slotting cutter having a disk-shaped cutting body with a plurality of non-identical insert receiving pockets and an equal number of identical indexable cutting inserts removably retained therein.

There is a need in the field for an improved rotary cutting tool having a disk-shaped cutting body with a plurality of identical insert receiving pockets and an equal number of identical indexable cutting inserts removably retained therein.

There is a need in the field for an improved rotary cutting tool in which each indexable cutting insert is retained in its respective insert receiving pocket with a high level of stability.

There is a need in the field for an improved rotary cutting tool capable of performing cutting operations at high feed rates.

In accordance with the present invention, there is provided an indexable cutting insert comprising:.

For a better understanding, the invention will now be described, by way of example only, with reference to the accompanying drawings in which chain-dash lines represent cut-off boundaries for partial views of a member and in which:.

As shown in <FIG>, the present invention relates to a cutting tool <NUM> comprising a disk-shaped cutting body <NUM> having an axis of rotation R defining a direction of rotation DR about the axis of rotation R, two opposing first and second body end surfaces 24a, 24b and a body peripheral surface <NUM> extending therebetween.

A median plane M perpendicular to the axis of rotation R intersects the body peripheral surface <NUM>, and first and second planes P1, P2 are equidistantly offset from opposite first and second sides S1, S2 of the median plane M, respectively.

In some embodiments of the present invention, neither of the first and second planes P1, P2 may intersect the cutting body <NUM>.

In other embodiments of the present invention (not shown), the first and second planes P1, P2 may be annular shaped, thus ensuring that neither of the first and second planes P1, P2 intersect a raised central portion of the cutting body <NUM>.

According to a first aspect of the present invention, as shown in <FIG>, a plurality of identical insert receiving pockets <NUM> are circumferentially spaced about the body peripheral surface <NUM> and an equal number of identical indexable cutting inserts <NUM> are removably retained therein.

By virtue of the plurality of identical insert receiving pockets <NUM> being identical, it should be appreciated that the cutting body <NUM> can be simply and cost-effectively manufactured.

In some embodiments of the present invention, the body peripheral surface <NUM> may have a total of N insert receiving pockets <NUM> and exhibit N-fold rotational symmetry about the axis of rotation R.

Also in some embodiments of the present invention, the cutting tool <NUM> may exhibit N/<NUM>-fold rotational symmetry about the axis of rotation R.

It should be appreciated that for embodiments of the present invention in which the cutting tool <NUM> exhibits N/<NUM>-fold rotational symmetry about the axis of rotation R, N is an even number.

In some embodiments of the present invention, the cutting inserts <NUM> may be manufactured by a suitably hard material, preferably by form pressing and sintering a cemented carbide, such as tungsten carbide, and the cutting body <NUM> may be manufactured from a less hard material.

As shown in <FIG>, each insert receiving pocket <NUM> opens out to the first and second body end surfaces 24a, 24b, and has a seat surface <NUM> and a back wall <NUM> shown in this embodiment as being transverse to the seat surface <NUM>.

Also, as shown in <FIG>, each insert receiving pocket <NUM> may open out to a chip gullet <NUM>, and each chip gullet <NUM> may be located rotationally forward of its respective insert receiving pocket <NUM>, thus aiding chip evacuation.

In some embodiments of the present invention, each insert receiving pocket's back wall <NUM> may be perpendicular to the median plane M.

Also in some embodiments of the present invention each insert receiving pocket's back wall <NUM> may face in the direction of rotation DR.

As shown in <FIG>, each insert receiving pocket's seat surface <NUM> may have a floor surface <NUM> and first and second lateral support surfaces 38a, 38b transverse thereto, and the first and second lateral support surfaces 38a, 38b may be located on the first and second sides S1, S2 of the median plane M, respectively.

In some embodiments of the present invention, the floor surface <NUM> and the first and second lateral support surfaces 38a, 38b of each seat surface <NUM> may be contiguous with their respective chip gullet <NUM>.

Also in some embodiments of the present invention, the floor surface <NUM> and the first and second lateral support surfaces 38a, 38b may be formed in a central recess <NUM> of the seat surface <NUM>, and the first and second lateral support surfaces 38a, 38b may face towards each other.

Further in some embodiments of the present invention, the first and second lateral support surfaces 38a, 38b may extend parallel to the median plane M. For such embodiments, the plurality of identical seat surfaces <NUM> can be simply and cost-effectively manufactured.

Yet further in some embodiments of the present invention, each seat surface <NUM> may include a planar raised shoulder surface <NUM> partially surrounding the central recess <NUM>.

As shown in <FIG>, each cutting insert <NUM> has opposing upper and lower surfaces <NUM>, <NUM> and an insert peripheral surface <NUM> therebetween and an insert axis A1 extending therethrough.

In some embodiments of the present invention, a through bore <NUM> coaxial with the insert axis A1 may intersect the upper and lower surfaces <NUM>, <NUM>.

Also in some embodiments of the present invention, each cutting insert <NUM> may not exhibit rotational symmetry about its insert axis A1.

As shown in <FIG>, the lower surface <NUM> has a bearing surface <NUM> and first and second lower abutment surfaces 52a, 52b transverse thereto.

In some embodiments of the present invention, the first and second lower abutment surfaces 52a, 52b may be spaced apart.

Also in some embodiments of the present invention, the first and second lower abutment surfaces 52a, 52b may be planar.

As shown in <FIG>, the bearing surface <NUM> and the first and second lower abutment surfaces 52a, 52b may be formed on a central boss <NUM> protruding from the lower surface <NUM>.

In some embodiments of the present invention, the bearing surface <NUM> may comprise at least two coplanar bearing sub-surfaces 53a, 53b.

Also in some embodiments of the present invention, the lower surface <NUM> may include a planar bottom surface <NUM> surrounding the central boss <NUM>.

As shown in <FIG>, in a bottom view of one of the cutting inserts <NUM>, the first and second lower abutment surfaces 52a, 52b form an obtuse first tilt angle α1.

In some embodiments of the present invention, the first tilt angle α1 may be greater than <NUM> degrees and less than <NUM> degrees, and with <NUM> degrees shown in the illustrated example of <FIG>.

Also in some embodiments of the present invention, the first tilt angle α1 may be an internal angle.

It should be appreciated that use of the term "internal angle" throughout the description and claims refers to an angle between two planar surface components or zones as measured internal to the member on which the surface components or zones are formed, respectively.

As shown in <FIG>, the insert peripheral surface <NUM> has opposing first and second insert end surfaces 54a, 54b spaced apart by opposing first and second insert side surfaces 56a, 56b, with first and second cutting edges 58a, 58b formed at the intersection of the upper surface <NUM> and the first and second insert end surfaces 54a, 54b, respectively.

In some embodiments of the present invention, the first cutting edge 58a may be interrupted by a first chip dividing notch 60a, and the second cutting edge 58b may be interrupted by a second chip dividing notch 60b.

Also in some embodiments of the present invention, the first and second insert end surfaces 54a, 54b may converge towards the first insert side surface 56a, and the first and second lower abutment surfaces 52a, 52b may face in the same direction as the second insert side surface 56b.

Further in some embodiments of the present invention, each cutting insert <NUM> may exhibit mirror symmetry about a vertical plane PV containing its insert axis A1 and intersecting its first and second insert side surfaces 56a, 56b.

According to the first aspect of the present invention, as shown in <FIG>, each cutting insert's lower surface <NUM> is in contact with the seat surface <NUM> of its respective insert receiving pocket <NUM>, and circumferentially adjacent cutting inserts <NUM> have a different one of their first and second insert end surfaces 54a, 54b in contact with the back wall <NUM> of their respective insert receiving pocket <NUM>.

In some embodiments of the present invention, a clamping screw <NUM> may extend through the through bore <NUM> and threadingly engage a screw bore <NUM> in the seat surface <NUM>.

Also in some embodiments of the present invention, as shown in <FIG> and <FIG>, the screw bore <NUM> may be formed in the floor surface <NUM>.

Further in some embodiments of the present invention, the screw bore <NUM> may have a screw axis A2 contained in the median plane M.

Yet further in some embodiments of the present invention, the insert axis A1 of each cutting insert <NUM> may be non-coaxial with the screw axis A2 of its respective insert receiving pocket <NUM>, and thus each through bore <NUM> may be eccentrically positioned in relation to its respective screw bore <NUM>.

Yet still further in some embodiments of the present invention, each insert's bearing surface <NUM> may be in contact with the floor surface <NUM> of its respective insert receiving pocket <NUM>.

As shown in <FIG>, the bottom surface <NUM> may be spaced apart from the raised shoulder surface <NUM> by a gap G.

As shown in <FIG>, the median plane M may intersect the first and second cutting edges 58a, 58b of each cutting insert <NUM>.

In some embodiments of the present invention, as shown in <FIG>, each cutting insert's vertical plane PV may be non-perpendicular to the median plane M, albeit with a deviation of <NUM> degree therefrom.

According to the first aspect of the present invention, as shown in <FIG>, the first plane P1 only intersects the first cutting edge 58a of every circumferentially alternate cutting insert <NUM> at a first intersection point I1 and none of the second cutting edges 58b, and the second plane P2 only intersects the second cutting edge 58b of every circumferentially alternate cutting insert <NUM> at a second intersection point I2 and none of the first cutting edges 58a.

As shown in <FIG>, the first and second cutting edges 58a, 58b intersecting the first and second planes P1, P2, respectively, may be operative and associated with first and second insert end surfaces 54a, 54b, respectively, not in contact with the back wall <NUM>.

It should be appreciated that once the operative first and second cutting edges 58a, 58b become worn, each cutting insert <NUM> may be indexed in its respective insert receiving pocket <NUM>, such that the unworn first and second cutting edges 58a, 58b become operative.

Alternatively, it should be appreciated that once the operative first and second cutting edges 58a, 58b become worn, each cutting insert <NUM> may be relocated to another insert receiving pocket <NUM>, such that the unworn first and second cutting edges 58a, 58b become operative, although the operator must ensure that the first plane P1 only intersects the first cutting edge 58a of every circumferentially alternate cutting insert <NUM> and none of the second cutting edges 58b, and the second plane P2 only intersects the second cutting edge 58b of every circumferentially alternate cutting insert <NUM> and none of the first cutting edges 58a.

In some embodiments of the invention, the first chip dividing notches 60a associated with the operative first cutting edges 58a may be located on one side of the median plane M, and the second chip dividing notches 60b associated with the operative second cutting edges 58b may be located on the opposite side of the median plane M.

It should be appreciated that the first and second chip dividing notches 60a, 60b provide the operator with a useful visual indictor, when indexing and replacing the cutting inserts <NUM>.

It should also be appreciated that the inclusion of different recessed or embossed shapes or letters, for example, "R" and "L" adjacent the first and second cutting edges 58a, 58b, respectively, provides the operator with an alternative visual indicator.

As shown in <FIG>, each first cutting edge 58a may have first and second end points NE1, NE2 located on opposite sides of the median plane M, and each second cutting edge 58b may have third and fourth end points NE3, NE4 located on opposite sides of the median plane M.

In some embodiments of the present invention, the first end point NE1 of each operative first cutting edge 58a may be contained in the first plane P1 and thus coincident with its associated first intersection point I1, and the third end point NE3 of each operative second cutting edge 58b may be contained in the second plane P2 and thus coincident with its associated second intersection point I2. For such embodiments of the present invention, the lateral distance between the first and second planes P1, P2 may define a maximum tool cutting width WMAX of the cutting tool <NUM>.

As shown in <FIG>, the second end point NE2 of each operative first cutting edge 58a may be located a first cutting width W1 from the first plane P1, and the fourth end point NE4 of each operative second cutting edge 58b may be located a second cutting width W2 from the second plane P2.

In some embodiments of the present invention, the first cutting width W1 may be at least nine tenths of the maximum tool cutting width WMAX, i.e. W1 ≥ WMAX*<NUM>/<NUM>, and the second cutting distance W2 may be at least nine tenths of the maximum tool cutting width WMAX i.e. W2 ≥ WMAX*<NUM>/<NUM>.

Also in some embodiments of the present invention, the first cutting distance W1 may be equal to the second cutting distance W2.

As shown in <FIG>, each operative first cutting edge 58a may have an inclined first end portion 66a extending from its first end point NE1 and forming an acute first end angle β1 of less than <NUM> degrees with median plane M, and each operative second cutting edge 58b may have an inclined second end portion 66b extending from its third end point NE3 and forming an acute second end angle β2 of less than <NUM> degrees with median plane M.

In some embodiments of the present invention, the first and second end angles β1, β2 may be equal.

It should be appreciated that for embodiments of the present invention having first and second end angles β1, β2 of less than <NUM> degrees, the cutting chip thickness will be suitably and advantageously reduced.

In some embodiments of the present invention, the inclined first end portion 66a of each operative first cutting edge 58a may laterally overlap the second cutting width W2, and the inclined second end portion 66b of each operative second cutting edge 58b may laterally overlap the first cutting width W1.

It should be appreciated that for embodiments of the present invention in which the inclined first and second end portions 66a, 66b laterally overlap the second and first cutting widths W2, W1, respectively, the operative first and second cutting edges 58a, 58b may be considered 'fully effective', enabling the cutting tool <NUM> to perform cutting operations at suitably and advantageously high feed rates.

In some embodiments of the present invention, the first lower abutment surface 52a of each cutting insert <NUM> having its first cutting edge 58a operative, may be in contact with one of the first and second lateral support surfaces 38a, 38b located on one of the first and second sides S1, S2 of the median plane M, and the second lower abutment surface 52b of each cutting insert <NUM> having its second cutting edge 58b operative, may be in contact with one of the first and second lateral support surfaces 38a, 38b located on the other one of the first and second sides S1, S2 of the median plane M.

Also in some embodiments of the present invention, the second lower abutment surface 52b of each cutting insert <NUM> having its first cutting edge 58a operative (e.g., see the lower part of <FIG>), may not be in contact with any of the first and second lateral support surfaces 38a, 38b, and the first lower abutment surface 52a of each cutting insert <NUM> having its second cutting edge 58b operative (e.g., see the upper part of <FIG>), may not be in contact with any of the first and second lateral support surfaces 38a, 38b.

It should be appreciated that apart from the bearing surface <NUM> being in contact with the floor surface <NUM> and one of the first and second lower abutment surfaces 52a, 52b being in contact with one of the first and second lateral support surfaces 38a, 38b, no other portion of each insert's lower surface <NUM> is in contact with the seat surface <NUM> of its respective insert receiving pocket <NUM>.

It should also be appreciated that for embodiments of the present invention in which the back wall <NUM> of each insert receiving pocket <NUM> is perpendicular to the median plane M and the first and second lateral support surfaces 38a, 38b of each insert receiving pocket <NUM> extend parallel to the median plane M, by virtue of one of the first and second insert end surfaces 54a, 54b being in contact with the back wall <NUM>, and one of the first and second lower abutment surfaces 52a, 52b being in contact with one of the first and second lateral support surfaces 38a, 38b, each cutting insert <NUM> is retained its respective insert receiving pocket <NUM> with a high level of stability.

In some embodiments of the present invention, the first lower abutment surface 52a of each cutting insert <NUM> having its first cutting edge 58a operative, may be in contact with the second lateral support surface 38b, and the second lower abutment surface 52b of each cutting insert <NUM> having its second cutting edge 58b operative, may be in contact with the first lateral support surface 38a.

Also in some embodiments of the present invention, the first lower abutment surface 52a of each cutting insert <NUM> having its first cutting edge 58a operative, may be entirely located further from the first intersection point I1 than the second lower abutment surface 52b, and the second lower abutment surface 52b of each cutting insert <NUM> having its second cutting edge 58b operative, may be entirely located further from the second intersection point I2 than the first lower abutment surface 52a.

It should be appreciated that for embodiments of the present invention in which the operative first or second lower abutment surface 52a, 52b of each cutting insert <NUM> is on the opposite side of the median plane M from its associated first or second intersection point I1, I2, and further away from its associated first or second intersection point I1, I2 than its adjacent non-operative second or first lower abutment surface 52b, 52a, the second or first lateral support surface 38b, 38a against which the operative first or second lower abutment surface 52a, 52b contacts, advantageously counteracts the moment on the cutting insert <NUM> caused by unbalanced cutting forces, which include cutting force components directed through the first and second intersection points I1, I2.

According to an additional aspect of the present invention, as shown in <FIG>, in a cross-section taken in a horizontal plane PH perpendicular to the insert axis A1 and intersecting the insert peripheral surface <NUM> of one of the cutting inserts <NUM>:.

In some embodiments of the present invention, the first and second lateral sides SL1, SL2 may be equal in length, and the imaginary acute trapezoid T may be an isosceles trapezoid.

Also in some embodiments of the present invention, the horizontal plane PH may be located closer to the upper surface <NUM> than to the lower surface <NUM>, and as shown in <FIG>, no portion of the cutting insert <NUM> below the horizontal plane PH may extend outside the imaginary acute trapezoid T.

Further in some embodiments of the present invention, the first and second lateral sides SL1, SL2 may be bisected by first and second lateral bisectors BL1, BL2, and the first and second lateral bisectors BL1, BL2 may form an obtuse second tilt angle α2.

Yet further in some embodiments of the present invention, the second tilt angle α2 may be equal to the first tilt angle α1.

As shown in <FIG>, the first and second end points NE1, NE2 of the first cutting edge 58a define an imaginary first straight line L1, and the third and fourth end points NE3, NE4 of the second cutting edge 58b define an imaginary second line L2.

In some embodiments of the present invention, the imaginary first straight line L1 may be parallel to one of the first and second lateral sides SL1, SL2, and the imaginary second straight line L2 may be parallel to one of the first and second lateral sides SL1, SL2.

As shown in <FIG>, the imaginary first straight line L1 is parallel to the first lateral side SL1, and the imaginary second straight line L2 is parallel to the second lateral side SL2.

According to the "additional" aspect of the present invention described above with respect to <FIG>, and with further reference to <FIG>, in the bottom view of one of the cutting inserts <NUM>, the first and second lower abutment surfaces 52a, 52b are located inside the imaginary acute trapezoid T.

In some embodiments of the present invention, the first and second lower abutment surfaces 52a, 52b may be entirely located inside the imaginary acute trapezoid T and not intersect the insert peripheral surface <NUM>.

Also in some embodiments of the present invention, as shown in <FIG>, imaginary third and fourth straight lines L3, L4 extending parallel to the first and second lower abutment surfaces 52a, 52b, respectively, may be perpendicular to the first and second lateral sides SL1, SL2, respectively.

As shown in <FIG>, the first and second insert end surfaces 54a, 54b may include first and second end abutment surfaces 68a, 68b.

In some embodiments of the present invention, as shown in <FIG>, the horizontal plane PH may intersect the first and second end abutment surfaces 68a, 68b.

As shown in <FIG>, circumferentially adjacent cutting inserts <NUM> may have a different one of their first and second end abutment surfaces 68a, 68b in contact with the back wall <NUM> of their respective insert receiving pocket <NUM>, and also such that each insert's horizontal plane PH intersects the back wall <NUM> of its respective insert receiving pocket <NUM>.

In some embodiments of the present invention, the first and second end abutment surfaces 68a, 68b may be planar.

Also in some embodiments of the present invention, as shown in <FIG> and <FIG>, a first end plane E1 defined by the first end abutment surface 68a may contain the first lateral side SL1, and a second end plane E2 defined by the second end abutment surface 68b may contain the second lateral side SL2.

Further in some embodiments of the present invention, the second end abutment surface 68b may be located on one side of the first end plane E1 and no portion of the cutting insert <NUM> may extend to the other side thereof, and the first end abutment surface 68a may be located on one side of the second end plane E2 and no portion of the cutting insert <NUM> may extend to the other side thereof.

As shown in <FIG>, the first and third peripheral corner points NC1, NC3 define the end points of a short base BS of the acute trapezoid T, and the second and fourth peripheral corner points NC2, NC4 define the end points of a long base BL of the acute trapezoid T.

As shown in <FIG>, the first and second lower abutment surfaces 52a, 52b may face towards the long base BL.

In some embodiments of the present invention, the first and second lower abutment surfaces 52a, 52b may be entirely located on opposite sides of a base bisector BB bisecting at least one of the short and long bases BS, BL.

Also in some embodiments of the present invention, the vertical plane PV may contain the base bisector BB.

Claim 1:
An indexable cutting insert (<NUM>) comprising:
opposing upper and lower surfaces (<NUM>, <NUM>) and an insert peripheral surface (<NUM>) therebetween and an insert axis (A1) extending therethrough,
the lower surface (<NUM>) having a bearing surface (<NUM>) and first and second lower abutment surfaces (52a, 52b) transverse thereto, and
the insert peripheral surface (<NUM>) having opposing first and second insert end surfaces (54a, 54b) spaced apart by opposing first and second insert side surfaces (56a, 56b), with first and second cutting edges (58a, 58b) formed at the intersection of the upper surface (<NUM>) and the first and second insert end surfaces (54a, 54b), respectively,
characterized in that:
in a cross-section taken in a horizontal plane (PH) perpendicular to the insert axis (A1) and intersecting the insert peripheral surface (<NUM>):
first and second peripheral corner points (NC1, NC2) formed at the intersection of the first insert end surface (54a) and the first and second insert side surfaces (56a, 56b), respectively, define the end points of a first lateral side (SL1) of an imaginary acute trapezoid (T),
third and fourth peripheral corner points (NC3, NC4) formed at the intersection of the second insert end surface (54b) and the first and second insert side surfaces (56a, 56b), respectively, define the end points of a second lateral side (SL2) of the imaginary acute trapezoid (T), and
the first and third peripheral corner points (NC1, NC3) define the end points of a short base (BS) of the acute trapezoid (T), and the second and fourth peripheral corner points (NC2, NC4) define the end points of a long base (BL) of the acute trapezoid (T),
and in a bottom view of the cutting insert (<NUM>):
the first and second lower abutment surfaces (52a, 52b) form an obtuse first tilt angle (α1) and are located inside the imaginary acute trapezoid (T).