Patent ID: 7172375

Claim:
A machine tool comprising: a spindle with a tool attached thereto; a machining unit by which said spindle is supported to be relatively movable in X-axis, Y-axis, and Z-axis directions; and a long bed which has a plurality of machining areas arranged in one direction and on which said machining unit is mounted, wherein said machining unit is movable in an arrangement direction of the machining areas, said machining unit is disposed on said bed to be bridged over a machining table and supports said spindle, said machining unit further including: a gate-shaped column in which right and left column main bodies disposed on said bed are coupled by front and rear cross frames; a cross rail having a rectangular shape in a plan view disposed between the front and rear cross frames and supported by the right and left column main bodies so as to be movable in at least one of the X-axis and Y-axis directions; a cylindrical saddle supported to be movable in at least one of the X-axis and the Y-axis directions in said cross rail; and a ram supported to be movable in the Z-axis direction in the saddle, wherein said spindle is attached to a lower end portion of said ram, wherein the right and left column main bodies each have a substantially rectangular shape, wherein one of the right and left column main bodies has an access opening sized to allow access to an operator therethrough, wherein the other one of the right and left column main bodies has a tool change window provided in a portion facing a tool change position, and a tool change arm can automatically change a tool attached to said spindle to a subsequent process tool held by a tool magazine through said tool change window, and wherein said cross rail has left and right flange portions supported by guide rails provided on upper surfaces of said right and left column main bodies.