Machining unit with rotary head carrying pivoting tools

Rotary head machining unit holding at least two pivoting tools for machining a non-rotating part centered on the axis of rotation of the head, comprising:

• a frame to which is rotatably mounted a rotor comprising the rotary head and a spindle integral with the rotary head, the rotor having an axial conduit and being connected to rotary drive means;
• axial means for guiding said part, said means being attached with bearings to the spindle or the rotary head;
• means for maintaining and axially displacing the part;
• at least two tool supports attached to the rotary head so as to pivot around respective axes parallel to the axis of rotation, each support having a transversely disposed control lever;
• and means for separately controlling pivoting which cooperate with said levers and comprise at least one annular rotary control element which is movable in axial translation within the rotor and is connected to a translation control device, and at least two sliding contact means each of which is associated with a respective one of said control levers and comprises a pair of surfaces located on the respective control lever and on the respective annular rotary control element, said pair of surfaces comprising a guiding surface and a contact surface resting on the guiding surface in a position which varies as a function of translation of the annular rotary control element, characterized in that each guiding surface (26a-26d) corresponding to a pivoting tool support (6a-6d) is shaped as a portion of a helix, the axis of which corresponds with the pivoting axis (7a-7d) of said support.