The head compensates for variations in flatness of a table upon which a glass sheet is placed for scoring, and also compensates for bending of the rails or support structure which carry the head as it traverses the table. A jump wheel is provided on a first arm pivotally mounted in the head, which head...http://www.google.fr/patents/US4098155?utm_source=gb-gplus-shareBrevet US4098155 - Self-compensating scoring head
