Patent attributes
Step portions with an L-shaped section each having a vertical restriction surface and a horizontal engagement surface are provided on both sides of a main body portion of a tool. On one side of a holding portion placing and holding a mounted tool to be exchanged, a first engagement member has a first engagement projection piece that opposes the engagement surface of one of the step portions, and has an end surface in abutment against the restriction surface. On the other side of the holding portion, a second engagement member has a second engagement projection piece having its intermediate part opposed to the engagement surface of the other of the step portions, and end surfaces on both sides are in abutment against the outer periphery of the main both portion on both sides thereof. The first and second engagement members are movable between an engagement position and a withdrawal position with respect to the step portions.