O-rings for vehicle fuel tank filler neck caps

Abstract

Resilient O-ring seals for caps for closing vehicle fuel tank filler necks, the fuel caps having shank portions extending into the necks. The radial width of the annular space between the inner wall of such a neck and the outer wall of the shank is less than the radial dimension of the O-ring. Each O-ring includes an annular, radially outwardly facing groove defined by an axially inner lip, an axially outer lip, and a connecting web portion. As the shank with the O-ring thereon moves axially into the neck, the axially inner surface of the inner lip contacts the neck and is urged axially outwardly in a wiping action causing bending of the O-ring such that its radially inner surface is resiliently urged radially and compressively to seal the annular space. In one embodiment, the inner surface of the outer lip contacts the neck as the shank and O-ring are projected further into the neck. The outer lip of the O-ring thereby axially compressively seals the space. In other embodiments, the outer surface of the inner lip and the inner surface of the outer lip include compression rings or beads. Axially outward deflection of the inner lip causes its compression ring to contact one of the walls defining the annular groove, creating an additional seal. In two of these 'compression ring' embodiments, the outer lip compresssion ring cooperates with the inner lip compression ring to create the additional seal.