A passive needle guard includes a body having a cavity therein for receiving a syringe, and a shield. The body is slidable with respect to the shield between retracted and extended positions covering, and exposing, respectively, a needle extending from the syringe, the body being biased towards the retracted...http://www.google.com/patents/US20050101917?utm_source=gb-gplus-sharePatent US20050101917 - Passive needle guard for syringes
