A utility knife has a protective guard that moves from a locked position to an unlocked position. Preferred mechanisms utilize a pawl that cooperates with a stop to reduce movement of the guard while the guard is in a locked position, and a simple latching mechanism that allows the pawl to bypass the...http://www.google.com/patents/US7356928?utm_source=gb-gplus-sharePatent US7356928 - Utility knife with safety guard having reduced play
