Patent ID: 8251243

Claim:
A pressure retaining closure for a pressurized vessel, comprising: a hub having an axis; a head having an inner surface and an outer surface and a peripheral edge, said head hingedly connected to said hub; a C-shaped locking ring, having a plurality of segments, disposed along said outer surface of said head in an angled head bearing surface adjacent to said peripheral edge; each of said segments having a polygonal cross-section including a radially inner surface and first and second fastening apertures extending through said radially inner surface of said segments; a C-shaped connecting ring, having a rectangular cross-section, positioned along said radially inner surfaces of said segments, said connecting ring having pairs of fastening apertures aligned with said first and second fastening apertures of each of said segments; wherein said radially inner surface of each of said segments defines a substantially cylindrical innermost surface supporting said C-shaped connecting ring and wherein said radially outer surface of each of said segments defines a frusto-conical locking ring outer surface; wherein said connecting ring is moveable to expand or collapse said locking ring from a first position, engaging said hub so that said frusto-conical locking ring outer surface engages an angled hub surface disposed at an angle to said axis for receiving said C-shaped locking ring, to a second position disengaging said hub allowing opening and closing of said head.