Cutting tool assembly having an exchangeable adaptor

A cutting tool assembly comprising a tool shank which has a cylindrical shape at least adjacent a leading end thereof and which has a shank holding portion, and an exchangeable adaptor oriented transversely with respect to the tool shank and having a partially circular circumference conforming with the cylindrical shape thereof, said adaptor having an adaptor mounting portion to be secured to the shank holding portion with clamping means, and an insert retaining portion for retaining a replaceable cutting insert, the insert retaining portion projecting outwardly from the adaptor mounting portion;

• said adaptor mounting portion having a side wall formed with a protrusion which has a protrusion abutting surface substantially parallel to the side wall, and opposite upper and lower protrusion retaining surfaces oriented transversely to the protrusion abutting surface;
• said shank holding portion having a face surface generally parallel to the side wall of the adaptor mounting portion and formed with a recess mating with and capable of receiving the protrusion of the adaptor mounting portion, the recess having a recess abutment surface and opposite upper and lower recess retaining surfaces adapted to interact with the corresponding surfaces of the protrusion;
• said clamping means comprising an adaptor through bore formed adjacent a rear end of the adaptor and passing through the protrusion, a threaded bore formed in the shank holding portion and aligned with the adaptor through bore, and a clamping screw having a screw head portion receivable within the adaptor through bore and a screw thread portion adapted for being screwed into the threaded bore;
• said rear end of the adaptor is formed with a transverse slit merging with the adaptor through bore, and at least a portion of said through bore, which is disposed in said protrusion, tapers in the direction towards said protrusion abutting surface of the adaptor mounting portion, said screw head portion being capable of bearing against the tapered portion of the through bore.

A cutting tool assembly comprising a tool shank having a shank holding portion and an exchangeable adaptor having an adaptor mounting portion to be secured to the shank holding portion with clamping means, and an insert retaining portion for retaining a replaceable cutting insert, the insert retaining portion projecting outwardly from the adaptor mounting portion;

• said adaptor mounting portion having a side wall formed with a protrusion which has a protrusion abutting surface and opposite upper and lower protrusion retaining surfaces;
• said shank holding portion having a face surface formed with a recess mating with and capable of receiving the protrusion of the adaptor mounting portion, the recess having a recess abutment surface and opposite upper and lower recess retaining surfaces adapted to interact with the corresponding surfaces of the protrusion;
• and
• said clamping means comprising an adaptor through bore formed adjacent a rear end of the adaptor and passing through the protrusion, a threaded bore formed in the shank holding portion and aligned with the adaptor through bore, and a clamping screw having a screw head portion receivable within the adaptor through bore and a screw thread portion adapted for being screwed into the threaded bore;
• and wherein
• said adaptor is provided with a transverse slit which merges with said adaptor through bore, the transverse slit passing between said opposite upper and lower protrusion retaining surfaces which interact with said opposite upper and lower recess retaining surfaces, when the adaptor is received into the recess of the shank holding portion.