Tool holder positioning device and machine tool having the same

A tool holder positioning device configured to be disposed on a machine head device of a machine tool and configured for installation of a tool holder device, said tool holder positioning device comprising:

• a first adapting member configured to be disposed on one of the machine tool and the tool holder device, and including a first base surface, and a protruding positioning portion extending outwardly from said first base surface along a first axis, said protruding positioning portion having a plurality of angularly spaced-apart first abutment areas surrounding the first axis, each of said first abutment areas having a first large arcuate edge a first small arcuate edge opposite to said first large arcuate edge along the first axis, and a first arcuate abutment surface between said first large arcuate edge and said first small arcuate edge, a distance between said first arcuate abutment surface and the first axis gradually decreasing from said first large arcuate edge to said first small arcuate edge, said first large arcuate edge being located between said first arcuate abutment surface and said first base surface;
• and
• a second adapting member configured to be disposed on the other one of the machine tool and the tool holder device, said second adapting member being removably disposed on said first adapting member and including a second base surface, and a recessed positioning portion extending inwardly from said second base surface along a second axis aligned with the first axis, said recessed positioning portion having a plurality of angularly spaced-apart second abutment areas surrounding the second axis and corresponding in number to said first abutment areas, each of said second abutment areas having a second large arcuate edge, a second small arcuate edge opposite to said second large arcuate edge along the second axis, and a second arcuate abutment surface between said second large arcuate edge and said second small arcuate edge, a distance between said second arcuate abutment surface and the second axis gradually decreasing from said second large arcuate edge to said second small arcuate edge, said second large arcuate edge being located between said second arcuate abutment surface and said second base surface;
• said tool holder positioning device being transitionable between an engaged state, in which said first adapting member is engaged to said second adapting member, and said first arcuate abutment surfaces of said first abutment areas respectively abut against said second arcuate abutment surfaces of said second abutment areas;
• and a disengaged state, in which said first adapting member is separated from said second adapting member.