Abstract: A machining center has a tool change device provided above a horizontally mobile column that has a main spindle for holding a tool. A circular tool magazine for carrying a plurality of tools in a horizontal attitude is provided on a support base which is positioned above the region in which the mobile column moves. The support base is supported in a cantilever fashion by posts erected on a bed. The tool magazine rotates within a horizontal plane for indexing tools to a standby position. The tools are accommodated in pots suspended via rolling members from the body of the tool magazine and adapted to move along a ring-shaped path under the tool magazine body. The tool magazine body has a local removal opening or cutout, from where a shifter at a standby position carries a pot to a tool delivery position.

Abstract: Tools are classified into small type tools that can pass through the space between a pair of grippers in its open position and large type tools that cannot pass through the space between the pair of grippers in the open position, when the headstock supporting a spindle holding a tool is moved to a position corresponding to a tool change position. When the next tool to be used is of the small type, the tool is moved through a standby position to the tool change position during a machining operation using the tool on the spindle, the headstock is moved to the position corresponding to the tool change position in response to a tool changing instruction and a predetermined tool changing operation is carried out.

Abstract: A tool magazine disclosed is fundamentally the same in construction as a corresponding prior art tool magazine but is capable of handling tools of diameters greater than those of tools which can be handled by the prior art tool magazine. The tool magazine comprise a magazine body provided with an endless guide groove, and a plurality of tool pots each for holding a tool, fixedly provided with guide members engaging the endless guide groove for sliding movement along the guide groove. Idlers are disposed between and in contact with adjacent tool pots, respectively, and supported in the endless guide groove so as to move along the endless guide groove. A feed mechanism moves the tool pots and the idlers along the endless guide groove with the idlers in contact with the guide members of the adjacent tool pots, respectively. The idlers are substantially the same in shape and dimensions as the guide members.