Hollow metallic sealing rings

Claim 1

A hollow, annular metallic sealing ring surrounding a central longitudinal axis generally perpendicular to a median plane of said ring, and comprising: radially spaced inner and outer portions of said ring, at least one of which portions is closed; said ring having a cross-sectional configuration of modified parabolic form when in a relaxed state, with a maximum depth along a center line of compression of said ring in a direction generally parallel to said axis, a width between said inner and outer portions along a radius from said axis and equal to substantially 7/8 of said maximum depth, each arm of said modified parabolic form diverging symmetrically on each side of said median plane from said closed portion and having a radius of curvature substantially equal to one-fourth of said maximum depth to the other of said inner and outer portions having a radius of curvature substantially equal to one-half of said maximum depth such that said arms converge, said inner and outer portions being joined on each arm by an intermediate portion having a radius of curvature substantially equal to said maximum depth.