US Patent 7326011 Contouring right angle head for complex machining

A right angle, modular machining head can be removably mounted on the too head of a CNC machining center to provide contour machining of a work piece around a C-axis. The modular head includes a rotating drive that moves the tool around a contour axis, producing nutational motion allowing close contouring of a work piece. The tool can be powered by a driven spindle on the tool head, or by a motor carried within the modular head. A locating connection between the modular head and the tool head, in combination with a position signals produced by a rotary encoder on the modular head registers the exact position of the tool within the coordinate reference system used by the machining center control system.