Abstract: A helical conical spring lock-washer includes a lock-washer body having formed on one surface thereof a plurality of triangular pyramid-shaped depressions. Each of the depressions provides a triangular opening formed on the respective surface of the lock-washer body, with the base of the triangular opening positioned adjacent to the outer margin of the lock-washer body and the apex of the triangular opening directed toward the center of the lock-washer body.

Abstract: Fluid flow control valves such as plug valves or cocks have the plugs thereof supported and sealed in the valve housing by a rigid but somewhat elastic plastics bearing member which is preloaded and compressed from its free state condition and seeks to reclaim this condition for taking up wear and preventing leakage in the valve assembly. The bearing member is preferably stretched over the plug and compressed in the housing by a retainer which is pressed into one end of the housing.