Annular seal

An annular seal of resilient elastomeric material having an open axially extending groove at one end between two interconnected body portions, said groove including oppositely disposed arcuate surfaces of approximately the same length and facing one another, each of said surfaces being on one of said body portions, one end of each of said arcuate surfaces merging into a groove bottom which has the shape of an end portion of an ellipse, an annular deformable biasing member generally circular in cross section located in said groove, said arcuate surfaces of the groove being in embracing contact with opposite surfaces of said biasing member at all times, said biasing member being spaced from said groove bottom when the seal is not under a compression load, at least one of said body portions having a sealing lip projecting in a radial direction at a location generally opposite from the longitudinal axis of said biasing member, the gap across the end of the groove remote from said groove bottom being substantially smaller than the diameter of said biasing member, said end portion of an ellipse at said groove bottom having embracing contact with a juxtaposed portion of said biasing member only when said sealing lip is under a compression load, said sealing lip being under a compression load only when the seal is mounted in an operative sealing position with a surface to be sealed.