Instrument panhead seal

Claim 1

In an instrument panhead having a chamber ending in an annular sealing region defined by a pair of angled interconnected surfaces opposed by a relatively rotatable surface spaced a fixed distance from one of said interconnected surfaces, an annular seal for said region comprising a unitary body formed of resilient Teflon material, said body having a pair of sealing surfaces in firm engagement with said pair of angled surfaces, said body being general generally U-shaped, in cross section, opening toward said chamber so that the bottom and one leg of the U define said pair of sealing surfaces, said body also having a sliding Surface formed by an annular lip, on the other leg of said body, in sealing movable contact with said rotatable surface so that the body provides a sealing barrier between said rotatable surface and said interconnected surfaces, said body being formed so that said other leg must be slightly deflected into said region and said sliding surface resiliently bears on said rotatable surface, and said body also being formed with a surface exposed to said chamber and extending from said sliding surface so that increases in pressure in said chamber tend to urge said sliding surface into contact with said rotatable surface.