A blade for a utility knife provides a cutting edge that is undulate, toothed, or otherwise multiply edged, but is not designed to be used with a sawing motion, and, because of its short length, would not be practically used with a sawing motion. Such a blade allows for easier cutting of a wider range...http://www.google.co.uk/patents/US20040187314?utm_source=gb-gplus-sharePatent US20040187314 - Utility knife blade having an uneven cutting edge
