Shear-vectoring design for composite casing end and removable, pressure-locking closure therefor

In the combination of an open-ended section of an internally pressurizeable casing and a closure assembly therefor, inset from said casing section end, wherein said closure assembly comprises a head, having opposed inner and outer surfaces and a peripheral surface connecting said surfaces, and a retaining means for said head seated in a groove in the interior surface of the casing-section wall,

• wherein said casing section is formed of helicallywound, resin-coated fibers and said groove is of generally semi-circular cross-section and defined by the adjacent surfaces of a pair of annular resin bodies, of generally triangular cross-section, the portions of said fibers passing over said resin bodies, to said open end, being bowed outwardly in conformation to them and defining an annular bulge, having an apex, in the outer surface of said section,
• the improvement comprising:
• (1) circumferentially wound fibers in said resin bodies, the resin and fibers together constituting hoops of resin-coated fibers,
• (2) a hoop of resin-coated fibers circumferentially wound around the portions of the helically-wound fibers between said casing-section end and the apex of said bulge,
• (3) as said retaining means, a ring, and
• (4) an annular concavity in said head defined by the juncture of said outer face and said peripheral surface and adapted to seat against and to lock in position said ring when urged against the same by internal pressurization of said casing, the portion of said surface between said concavity and said inner face being slidingly engaged with the inner surface of said casing section.