Apparatus for machining pipe ends, especially for cutting connecting threads

An apparatus for machining a pipe end comprising:

• a tool head rotatable about a pipe end and having an axis of rotation;
• a plurality of tool holders angularly equispaced about said axis and radially shiftable on said tool head;
• a respective machining tool engageable with the pipe end and clamped on each of said tool holders;
• a plurality of actuators extending parallel to said axis and displaceable relative to said tool head for shifting said tool holders, said actuators having extremities proximal to said pipe end and extremities remote from said pipe end, said extremities proximal to said pipe end having teeth;
• a frame common to and connected with said actuators at said extremities remote from said pipe end;
• respective racks on said tool holders, at least some of said racks meshing with the teeth of said actuators for radial displacement of said tool holders upon displacement of said actuators parallel to said axis relative to said tool head;
• pinion gears meshing with racks on said tool holders whereby said pinion gears mesh with racks of neighboring tool holders to couple the neighboring tool holders for joint radial movement or are individual to respective tool holders;
• and
• balancing weights integrated with said pinions and having centers of mass offset from rotation axes thereof.