A replaceable gang head machine tool unit having a driving motor, the unit being mounted on a slide table arranged to be driven and advance in a given direction wherein: there is provided an annular rail comprising a rear stationary rail and a front movable rail disposed on a machine base, a plurality of gang heads disposed around the annular rail and supported thereon, the plurality of gang heads being arranged to be rotated on the annular rail by an index table to permit any desired gang head to be selected therefrom on the movable rail. When the working unit is in a retreated position in the machine base, the selected head on the movable rail may be joined to the unit for travel therewith together with the movable rail.

A fully automated tool changer system for multi-station forging machines is disclosed. This system provides a tool and die supporting head providing spaced support rails on which the tools or dies are supported during the transfer between the machine and the tooling rack. Such head is operable to properly position tools and dies which have different diameters for insertion into the cylindrical cavities in which they are mounted within the machine. A second tooling head is rotated to an operative position when the elements of the shear are to be changed. The tool heads are directly supported on the machine frame or the tool rack so that the loads of installing and removing the tooling are directly transmitted to stationery supports and need not be absorbed by the power transfer system. Further, the supports are arranged so that a high degree of positional accuracy is provided during the tool changing operations. Powered clamping means are provided to releasably lock the tooling in its installed position and is structured to assure that adequate locking is provided without jamming. A flushing system is provided to insure that debris does not cause difficulty during the tool changing operations.

A numerically controlled machine tool system having a tool transfer device which, with a change in the kind of workpieces to be machined in a numerically controlled machine tool, operates to replace successively unnecessary dedicated tools in a tool magazine of the machine tool with next to be used dedicated tools supplied to the vicinity of the tool magazine. A central processor reads out from an external memory device one of the numerical control (NC) programs corresponding to the kind of a lot of workpieces to be machined and transmits the NC program to a numerical controller. In advance of the machining of a last one of the lot of workpieces, the central processor modifies the NC program by inserting respectively into correct portions of the NC program a number of replacing command data each instructing that one of the dedicated tools in the tool magazine designated by one of the replacing command data be replaced. When the numerical controller executes the modified NC program for machining the last one of the lot of workpieces, tool replacing operations according to the replacing command data are successively carried out. Accordingly, during the machining of the last one of the lot of workpieces, the dedicated tools in the tool magazine designated by the replacing command data are successively indexed to a tool replacing position of the tool magazine and are successively replaced by the transfer device with the next used dedicated tools in the vicinity of the tool magazine.

A multispindle-head machine tool has a column, a plurality of multispindle heads each having a plurality of tools and an engaging member and an annular feed passageway supporting the multispindle heads for circulatory movement therealong. The annular feed passageway includes a pair of upper and lower fixed guide members supported on the column, and a movable guide member movable back and forth horizontally for interconnecting ends of the upper and lower fixed guide members near a machining position. A rotary actuator is provided together with a feed mechanism disposed around the annular feed passageway and movable to circulate along the annular feed passageway by the rotary actuator for moving the multispindle heads along the annular feed passageway. An actuator unit is mounted on the column in association with the movable guide member for positioning one of the multispindle heads which is held on the movable guide member in the machining position, and rotating the tools of one of the multispindle heads. A jig table is mounted on a side of the column and horizontally movable back and forth. The jig table includes an attachment jig for supporting a workpiece to be machined by the tools of one of the multispindle heads.

The invention relates to a machine tool on which an extra working head can be exchanged readily. The machine tool comprises a main beam extending horizontally in leftward and rightward directions, a carrier mounted for leftward and rightward movement on the main beam, a ram mounted for upward and downward sliding movement on the carrier, at least one standing working head mounted for upward and downward movement on the carrier, a plurality of head holders, an extra working head held on each of the head holders, a sub beam extending in forward and backward directions and having a front portion and a rear portion defining therebetween a gap adjacent an end of the main beam, first guide means provided on the front and rear portions of the sub beam for guiding the head holders for the extra working heads in a forwardly and backwardly juxtaposed relationship for forward and backward sliding movement thereon, a carriage mounted on the sub beam for slidably moving the head holders along the first guide means, and second guide means provided on the ram for carrying a single head holder thereon.