A universal seal is shown with orbital movement of a center opening for use in endoscopic surgery. A two part seal housing encloses the universal seal in an annulus surrounding an insertion port. The outer periphery of the universal seal is clamped between the two parts at the outer edge of the annulus....http://www.google.com.au/patents/US5989224?utm_source=gb-gplus-sharePatent US5989224 - Universal seal for use with endoscopic cannula
