Patent ID: 8668413

Claim:
A coupler for a quick change rotary cutting tool assembly allowing a cutter having an anchor projecting from a rear stop face of the cutter abutting a centering portion to be quickly and releasably coupled to a shank having a centering portion within an internal mounting bore, the coupler comprising: a cylindrical portion supporting at a rear end a coaxial male threaded portion for engaging an internal threaded bore of the shank, and a transversal groove diametrically formed through the cylindrical portion and being open toward a front end surface of the cylindrical portion so as to form an open channel having opposing parallel walls dimensioned to accommodate opposing parallel flat surfaces of an anchor mounted on a rear end of the cutter; a partial inside surface of a first one of the walls and an angularly opposing partial inside surface of a second one of the walls being undercut toward a lower surface of the groove so as to form a pair of angularly offset recesses at respective opposite ends of the groove that engage a retaining surface of the anchor when the anchor is inserted into the groove and rotated in a locking direction.