Cutting tool assembly and cutting head therefor

A replaceable cutting head having an axis of rotation (A) defining a front-to-rear direction and a direction of rotation (R) and comprising:

• a cutting head cutting portion adjacent a cutting head front face and a mounting portion extending rearwardly therefrom, the mounting portion comprising at least two cutting head coupling portions;
• each cutting head coupling portion comprising a planar cutting head base surface extending transversely to the axis of rotation (A), a cutting head torque transmission wall extending generally radially inwardly from a cutting head cylindrical outer surface to a cutting head cylindrical inner wall and forwardly from the cutting head base surface, and a cutting head fixation wall extending rearwardly from and circumferentially along the cutting head base surface relative to the axis of rotation (A);
• each cutting head base surface comprising a cutting head first base portion extending generally inwardly from the cutting head cylindrical outer surface to the cutting head fixation wall, and from the cutting head torque transmission wall to a cutting head leading flute portion, and a cutting head second base portion co-planar with the cutting head first base portion and extending continuously circumferentially therefrom to a cutting head trailing flute section and inwardly from the cutting head cylindrical inner wall to the cutting head fixation wall.

A rotary cutting tool assembly comprising:

• a cutting head having:
• a first axis of rotation defining a front-to-rear direction and a direction of rotation (R);
• a first cylindrical outer surface and first leading and first trailing flute sections;
• a cutting portion adjacent a cutting head front face and a mounting portion extending rearwardly therefrom, the mounting portion comprising at least first and second cutting head coupling portions bounded by the first cylindrical outer surface and by the first leading and first trailing flute sections;
• the first and second cutting head coupling portions each comprising:
• a first planar base surface extending transversely to the first axis of rotation;
• a first torque transmission wall extending generally inwardly from the first cylindrical outer surface to a first cylindrical inner wall;
• and
• a first fixation wall extending rearwardly from the first planar base surface and circumferentially relative to the first axis of rotation;
• wherein
• the first planar base surface comprises a first base portion extending generally inwardly from the first cylindrical outer surface towards the fixation wall, and from the first torque transmission wall to an adjacent first leading flute section, and a second base portion co-planar therewith, extending inwardly from the first cylindrical inner wall to the first fixation wall, and circumferentially from an adjacent first trailing flute section towards the first base portion;
• and
• a shank having:
• a second axis of rotation;
• a second outer surface and second leading and second trailing flute sections;
• a receiving portion extending rearwardly from a shank front face, the receiving portion comprising at least first and second shank coupling portions bounded by the second cylindrical outer surface and by the second leading and second trailing flute sections;
• the first and second shank coupling portions each comprising:
• a second planar base surface extending transversely to the second axis of rotation;
• a second torque transmission wall extending generally inwardly from the second cylindrical outer surface to a second cylindrical inner wall;
• and
• a second fixation wall extending rearwardly from the second planar base surface and circumferentially relative to the second axis of rotation;
• wherein
• the second planar base surface comprises a first base portion extending generally inwardly from the second cylindrical outer surface towards the fixation wall, and from the second torque transmission wall to an adjacent second leading flute section, and a second base portion co-planar therewith, extending inwardly from the second cylindrical inner wall to the second fixation wall, and circumferentially from an adjacent second trailing flute section towards the second base portion;
• wherein:
• the assembly is adjustable from an initial position in which the cutting head and shank are separated, to a secured position in which the cutting head coupling portions and the shank coupling portions engage each other with their fixation walls, their torque transmission walls, their first base portions and their second base portions abutting each other.