A safety trocar device is described which has an internal safety shield within the obturator of the trocar. The internal safety shield is spring loaded to extend in the distal direction to cover the cutting tip of the trocar obturator. In one embodiment, the trocar obturator is made with a three-sided...http://www.google.de/patents/US5674237?utm_source=gb-gplus-sharePatent US5674237 - Safety trocar
