Patent ID: 6964547

Claim:
A tool holder apparatus, comprising: an elongated shank intended to be supported for rotation about a turning axis, said shank having an internal female frustoconical opening at a first end thereof, and an axial first bore having an inner end opening to said frustoconical opening; an elongated tool holder having a first end for supporting a cutting tool in a cutting position, an external male frustoconical structure receivable in the frustoconical opening of the shank, and a narrow second end having an expandable outer surface and axial slots; the narrow end of the tool holder has an axial bore therein; threaded camming structure movably mounted in the tool holder second bore; an elongated drawing member received in said first bore of the shank, the drawing member having an inner threaded end disposed in said frustoconical opening engageable with the threaded structure in the tool holder such that as the drawing member is turned about said turning axis in a first direction, the male end of the tool holder is moved toward a locked position in the female end of the shank, and as the drawing member is turned in the opposite direction, the tool holder is axially movable away from the shank; the tool holder having a second bore intersecting said first bore; the threaded structure in said second bore comprising; camming structure disposed in the second bore of the tool holder, the camming structure having a threaded bore for receiving the inner threaded end of the drawing member; and the camming structure being axially movable to a camming position in the second bore to expand the slotted narrow second end of the tool holder into engagement with the female opening of the shank; the drawing member being operative to move the camming structure to expand the male frustoconical structure in the female opening to a locked position.