An endoscope with an encircling sleeve slidably mounted in a needle-like trocar, at least the endoscope entering a body cavity under spring bias upon completion of a puncture by the trocar. Preferably, the viewing end of the endoscope is sealed within the sleeve and the trocar and sleeve are detachable...http://www.google.es/patents/US4254762?utm_source=gb-gplus-sharePatente US4254762 - Safety endoscope system
