Seal for relatively rotatable parts

A seal for placement about a shaft and for sealing clearance between the shaft and at least two close annular surfaces each adjacent an opening through which the shaft passes, the seal comprising:

• a ring-like body of stretchable material adapted to be stretched about the shaft when placed thereon and including a central portion and at least two annular lip portions extending generally radially outwardly of said central portion and movable relative thereto in a hinge-like manner, each lip portion defining a radially outermost edge and a sealing surface adjacent said edge for engaging a corresponding one of the close annular surfaces through which the shaft passes, each of the sealing surfaces being relatively short as measured from its said outermost edge, said body when in its undeformed condition defining a radially inwardly-facing wall of such configuration and of such cross-sectional shape that when said body is stretched from an undeformed condition to a deformed condition about the shaft, said radially inwardly-facing wall is forced generally flat against the shaft and each one of the lip portions moves from a first angular position to a second angular position relative to another one of said lip portions of said body so that when said seal is placed upon the shaft so that the sealing surface of each of said lip portions contacts a corresponding one of the close annular surfaces through which the shaft passes and each lip portion is thereby prevented from moving to its said second angular position, said lip portions are biased into sealing engagement with the annular surfaces.

In combination:

• a shaft having a cylindrical surface;
• means defining at least two close annular surfaces each defining an opening through which said shaft passes and continuous with another annular surface;
• and
• a seal in the form of a ring-like body of stretchable material stretched about the surface of said shaft and in sealing engagement therewith, said body including a central portion and at least two lip portions extending radially outwardly of said central portion and hingedly movable relative thereto, each of said lip portions defining a radially outermost edge and a sealing surface adjacent said edge, each of the sealing surfaces being relatively short as measured from its said outermost edge and being biased into sealing engagement with a corresponding one of said close annular surfaces by the stretched condition of said body so that said close annular surfaces and said lip portions collectively define an annular lubricant-trapping cavity between opposite sides of said seal.