A machine tool includes: a lower tool rest on which a plurality of tools are mounted; a motor provided at the lower tool rest, for rotating a rotating tool when the rotating tool is mounted on the lower tool rest; and a tool holder attached to the lower tool rest, for detachably holding the tool. The tool holder has a clamping mechanism portion operating between a clamping state of clamping the tool and an unclamping state of unclamping the tool, as a result of transmission of motive power generated at the motor. With such a configuration, the clamping mechanism portion for automatically clamping and unclamping the tool held in the tool holder on the tool rest is provided with a simple configuration.

An electronic drill with revolving replaceable drilling heads includes a housing, a driving unit, a rotary cover, and a plurality of drill heads. The housing has an opening, a through hole, a containing room connected therebetween. A motor container is disposed within the containing room to contain a motor of the driving unit. The rotary cover is assembled to the housing and is rotatable so that the plurality of drill heads coupled to the rotary cover is moveable freely in a rotary track between the motor container and the housing. One of the drill heads may be rotated to be aligned with a rotary hole of a gear set driven by the motor and pushed forward for use. The drill head can also be retracted backward and replaced in the electronic drill by rotating the rotary cover, so that another drill head can be pushed outward for use.

A tool replacement apparatus according to the present invention includes: a turning tool magazine capable of attaching or removing a tool to/from a spindle of a machine tool; a tool replacement control unit which controls operations of turning the tool magazine and attaching or removing a tool to/from a spindle; and a setting unit which sets a rotatable range of the tool magazine. The tool replacement control unit includes: a determining unit which determines whether or not a designated rotation angle in an instruction for turning the tool magazine is within the rotatable range set by the setting unit; and a unit which stops an operation of replacing a tool when the determining unit determines that a designated rotation angle is out of a rotatable range.

The present invention relates to embodiments of a machine tool, in particular a multi-spindle milling machine, comprise a machine frame, a workpiece clamping device for clamping a workpiece, an axis slide assembly arranged on the machine frame, and a spindle carrier assembly which is arranged on the machine frame and has at least two tool-carrying work spindles. The axis slide assembly is configured to linearly move the workpiece clamped at the workpiece clamping device by way of three controllable linear axes X, Y and Z. The work spindles are arranged at a turret which can be rotated or swiveled about a turret axis at respectively equal distance from the turret axis, and the spindle axes of the work spindles are aligned or can be aligned in parallel to one another and in parallel to the turret axis.