A surgical scalpel is provided with a retractable guard for its cutting blade. The scalpel includes a resiliently-biased locking means and a releasing mechanism for, alternatively, selectively locking the guard in an extended position for covering the blade and in a retracted position for exposing the...http://www.google.fr/patents/US5250063?utm_source=gb-gplus-shareBrevet US5250063 - Surgical scalpel with retractable guard
