The frame of an engraving machine supports a slide for movement in a first horizontal direction. A pantograph is pivoted to the slide for movement about a vertical axis. A tool holder is supported by the pantograph. The tool holder is prevented from pivoting so that inscribed lines will have different...http://www.google.es/patents/US4461082?utm_source=gb-gplus-sharePatente US4461082 - Engraving machine
