Abstract: A machine tool is provided with an exchange arm for automatically exchanging tools between a tool spindle and a tool magazine. A drive key and a detent pin protrude respectively from the tool spindle and each of the tool storage portions of the magazine and are engageable, with a predetermined play, with a key-way of each tool. A fine indexing device has a rotatable cam drum on which a first cam segment is formed for indexing the tool spindle to a predetermined angular position following a coarse indexing operation by a coarse indexing device. A second cam segment is further formed on the cam drum to rotate the tool spindle more than the play from said predetermined angular position after a fresh tool is inserted into the spindle, so that a positive engagement between the drive key and the key-way of the tool can be achieved.

Abstract: A machine tool is provided with an exchange arm for automatically exchanging tools between a tool spindle and a tool magazine. A drive key and a detent pin protrude respectively from the tool spindle and each of the tool storage portions of the magazine and are engageable, with a predetermined play, with a key-way of each tool. A fine indexing device has a rotatable cam drum on which a first cam segment is formed for indexing the tool spindle to a predetermined angular position following a coarse indexing operation by a coarse indexing device. A second cam segment is further formed on the cam drum to rotate the tool spindle more than the play from said predetermined angular position after a fresh tool is inserted into the spindle, so that a positive engagement between the drive key and the key-way of the tool can be achieved.

Abstract: A machine tool having a turret head equipped with a plurality of multiple spindle units on the support stations thereof with the exception of one station rotatably supporting a tool spindle adapted to removably receive a tool, a tool storage magazine storing a plurality of "single" tools, and tool changing apparatus for interchanging the tools between the tool spindle and the tool storage magazine. The turret head may be rotated to successively position one of the multiple spindle units or the tool spindle at an operating position that confronts with the workpiece supported on the worktable such that the multiple spindle unit or the single tool on a tool spindle performs the machining operation on the workpiece.