Tool clamping apparatus

A tool clamping apparatus for a machine tool used with a tool mounting attachment which is adapted to be clamped to a tool mounted part with an inwards narrower opening therein of the machine tool, said tool clamping apparatus comprising:

• a protruding portion and a connected portion formed integrally with said attachment, the protruding portion having an outer surface tapered so as to fit into said opening of the tool mounted part while the connected portion has a curved associated piece projecting externally thereround;
• a clamping cylindrical article which is provided inside said tool mounted part of the machine tool in such a manner as to be capable of rotating as well as moving axially forwards and backwards, the clamping cylindrical article having a curved associated piece projecting internally thereround, corresponding to said covered piece of the connected portion, wherein the clamping cylindrical article is caused to rotate for a predetermined angle when the associated piece of the clamping article overlaps the connected portion except for the associated piece of the attachment so that an engagement of both the curved associated pieces of the clamping cylindrical article and said connected portion opposite to one another is performed, whereby said attachment can be prevented from moving apart from the tool mounted part of the machine tool;
• and
• a rotational driving means for driving said clamping cylindrical article in both the predetermined and reverse rotational directions, the rotational driving means having a forcing mechanism which draws in the clamping article when rotated in a predetermined direction and pushes out the article when rotated in the reverse direction.