Rotary cutting tool, such as a drill, comprising an exchangeable cutting insert, and an exchangeable cutting insert
A rotary cutting tool that is composed of a tool shank with at least one chucking groove or chip flute and one exchangeable cutting insert. At the tip of the shank a recess for accommodating the cutting insert is provided. The tool shank, on its circumference, has a limb with a bearing surface that is inclined relative to the tool axis and that corresponds to a likewise inclined bearing surface on a wing of the cutting insert. The inclination of the bearing surfaces produces an axial force that retains the cutting insert on the tool shank.
1. A replaceable cutting insert for use with a generally cylindrical tool body in performing cutting operations when rotated about a central rotational axis, the cutting insert comprising:
a cutting tip portion comprising at least one cutting edge;
an elongated projection being disposed to project from a central section of the cutting tip portion along the central rotational axis, the elongated projection having a varying radius;
wherein the cutting tip portion comprises at least one wing disposed to extend in a substantially radial direction with respect to the central rotational axis and beyond an outer surface of the elongated projection;
wherein the at least one wing comprises:
a top tip surface and a bottom contact surface, the bottom contact surface being disposed opposite the top tip surface;
a peripheral surface being disposed to extend between the top tip surface and the bottom contact surface;
a side flute surface being disposed to extend between the top tip surface and the bottom contact surface; and
a side bearing surface being disposed opposite the side flute surface and being disposed to extend between the top tip surface and the bottom contact surface; and
wherein a cross-section of the elongated projection comprises a pair of elliptical shaped portions, each of the elliptical shaped portions being disposed on opposing sides thereof.
2. The replaceable cutting insert according to claim 1 , wherein the elongated projection generally tapers inward toward the central rotational axis as it extends from the central section.
3. The replaceable cutting insert according to claim 1 , wherein the elongated projection has a cross-section having a diminishing radius.
4. A cutting tool adapted to perform cutting operations when rotated about a central rotational axis, the cutting tool comprising:
a generally cylindrical tool body having an opening disposed at an end thereof; and
a cutting insert disposed on the tool body, the cutting insert comprising:
a cutting tip portion comprising at least one cutting edge;
an elongated projection extending from a central section of the cutting tip portion into the opening of the tool body along the central rotational axis, the elongated projection having a varying radius;
wherein the cutting tip portion comprises at least one wing disposed to extend in a substantially radial direction with respect to the central rotational axis and beyond an outer surface of the elongated projection;
wherein the at least one wing comprises:
a top tip surface and a bottom contact surface being disposed opposite the top tip surface;
a peripheral surface being disposed to extend between the top tip surface and the bottom contact surface;
a side flute surface being disposed to extend between the top tip surface and the bottom contact surface; and
a side bearing surface being disposed opposite the side flute surface and being disposed to extend between the top tip surface and the bottom contact surface; and
wherein a cross-section of the elongated projection comprises a pair of elliptical shaped portions, each of the elliptical shaped portions being disposed on opposing sides thereof.
5. The cutting tool according to claim 4 , wherein the elongated projection generally tapers inward toward the central rotational axis as it extends from the central section.
6. The cutting tool according to claim 4 , wherein the elongated projection has a cross-section having a diminishing radius.
7. The cutting tool according to claim 4 , wherein a cross-section of the elongated projection comprises a pair of concave shaped portions, each of the concave shaped portions being disposed on opposing sides thereof.
8. The replaceable cutting insert according to claim 1 , wherein a cross-section of the elongated projection comprises a pair of concave shaped portions, each of the concave shaped portions being disposed on opposing sides thereof.