Abstract: The invention concerns the work units for automatic machine tools in which a spindle (5) moves in translation and rotates with respect to a work axis (Z). More particularly in these units, in order to obtain the rotation/translation of the spindle, the latter is housed in a sleeve (3) that slides along the work axis (Z), with respect to which it is however free to turn.

Abstract: A work unit for automatic machine tools is provided with a spindle that moves in translation and rotates with respect to a work axis. The spindle is housed within a sleeve that is slidable along the work axis, with the spindle being rotatable within. Rotation of the spindle is controlled by a drive unit mounted directly on the spindle and arranged inside the sleeve, which eliminates the need for a separate transmission mechanism and thereby results in a simplified construction of the work unit and an increase in performance.

Abstract: For the change of tools of machine tool operating units, a device is provided which comprises a tool-holder support or carriage (144,204) on which there are mounted at least two tool-holder spindles (48,148) with a corresponding tool (50,150), and the axis of at least one of these at least two tool-holder spindles is inclined at a predetermined angle relative to the axis of the spindle (10,110) of the operating unit. Means controlled by the spindle (10,110) of the operating unit pivot this support or carriage (44,204) and the corresponding at least one tool-holder spindle (48,148) by this predetermined angle, in order to position the required tool-holder in axial alignment with this spindle (10,110).

Abstract: In a transfer machine tool with a rotary table, the machining units with horizontal axes are arranged in orientations which do not coincide with the radii of the rotary table and the workpieces being machined are mounted on piece-holder plates which are fixed to the rotary table but are rotatable about vertical axes perpendicular to the plane of the rotary table; for each advance of a workpiece being machined from one work station to the next, the respective plate is rotated through an angle of between 0.degree. and 45.degree. relative to the radius at the next station, the angle possibly being added algebraically to the angle of rotation necessary when the face of the workpiece to be machined is changed.