Butterfly valve apparatus

Claim 1

A butterfly valve comprising: a housing including a tubular portion for carrying fluid therethrough; a rotatable valve shaft arranged to penetrate said tubular portion perpendicularly to the axis thereof, said valve shaft being held in sleeve bearings located adjacent to opposite walls of said tubular portion and further including a drive stem with a rectangular cross section; a butterfly valve plate fixedly mounted on said rotatable valve shaft in said tubular portion; a lever system having an aperture arranged to receive the drive stem of said valve shaft and being capable of converting a rectilinear motion to a rotary motion; and means for oscillating said lever system the improvement wherein: said lever system has a rectangular means defining an opening including opposed longitudinal side dimensions which are perpendicular to the plane of said butterfly valve plate and transverse dimensions of said rectangular means defining the opening lies in planes parallel with said butterfly valve, said valve stem further including a stem portion of rectangular configuration complemental to said rectangular means defining the opening in said lever system and having a smaller longitudinal dimension than said lever system opening to thereby permit limited relative sliding movement of said complementally formed elements to thereby compensate for radial clearance in said bearings as well as to relieve pressure on the means motivating said lever system.