Patent ID: 7137939

Claim:
A machine tool having a boring bar magazine, comprising: a base of the machine tool; a main spindle having an axis directed substantially in a horizontal direction to a floor surface, said main spindle being provided with a chuck at a tip end; a headstock, positioned on one side out of right and left directions of the machine tool and provided on said base, for rotatably supporting said main spindle; a tool rest, provided on said base, being capable of supporting at least the boring bar and being movable in at least two directions of a first direction in parallel to the axis of said main spindle and a second direction perpendicular to the first direction; and a boring bar magazine, positioned on the other side out of the right and left directions of the machine tool and provided on said base, which stocks a single or a plurality of boring bars and performs swiveling and indexing operations, wherein the boring bar of said tool rest is moved in the at least two directions relative to the workpiece gripped by the chuck to thereby turn the workpiece, and said tool rest is moved to change the boring bars between said tool rest and said magazine at an index position, wherein a tool holder of the boring bar is mounted on a boring bar mounting portion provided on said tool rest and is clamped and unclamped by a clamping and unclamping mechanism, and said clamping and unclamping mechanism comprises: holder side tapered surfaces and holder side plain end faces continuous with the holder side tapered surfaces which are formed on said tool holder and extend, respectively, in a direction in parallel with a centerline of said tool holder; tool rest side tapered surfaces and tool rest side plain end faces continuous with the tool rest side tapered surfaces which are formed on said boring bar mounting portion of said tool rest and extend, respectively, in a direction in parallel with a centerline of said tool rest; and cylinder portions which are provided in said boring bar mounting portion and are controlled, wherein said tool holder is directly depressed by pistons of said cylinder portions whereby said holder side plain end faces and said holder side tapered surfaces are depressed against said tool rest side plain end faces and said tool rest side tapered surfaces, respectively, to thereby clamp said tool holder to said tool rest, wherein said tool rest is controlled so that the centerline of said tool rest is directed in a direction in parallel with a centerline of a magazine body portion when the boring bars are changed with each other between said tool rest and said magazine, and at this time, the centerline of said magazine body portion, the index position, said boring bar mounting portion, and the centerline of said tool rest are located on the same axis line.