Cutting tool assembly and a replaceable cutting head for use therein

A cutting tool assembly for rotary cutting operations comprising a replaceable cutting head and a tool shank, having a common longitudinal axis and mating peripheral surfaces;

• said cutting head having a cutting portion adjacent a leading end and a cutting head mounting portion adjacent a trailing end thereof, and said tool shank having a cutting head receiving portion formed at a front face thereof, said cutting head mounting portion and the cutting head receiving portion of the tool shank each having at least two coupling portions, the cutting head coupling portions and the tool shank coupling portions being bound by said peripheral surfaces and mating in shape and dimensions;
• each coupling portion having a base surface extending transversely to said longitudinal axis and adapted for participating in an axial support of the cutting head in the tool shank, a torque transmission wall extending in a generally radial direction relative to said longitudinal axis and oriented transversely to said base surface, and a fixation wall disposed adjacent and extending transversely to the torque transmission wall and circumferentially relative to said longitudinal axis, the fixation wall of each cutting head coupling portion having an angular extension smaller than a corresponding angular distance between adjacent extremities of the fixation walls of two different tool shank coupling portions;
• the cutting head coupling portions being insertable between the tool shank coupling portions into a first position, and being rotatable therefrom into a second position in which the cutting head coupling portions fully overlie the corresponding tool shank coupling portions with their base surfaces and torque transmitting walls abutting each other and their fixation walls co-axially interacting in an interlocking male-female fashion, providing thereby the self-clamping of the cutting head on the tool shank.