US Patent 7178786 Stem construction for rotatable valve body

A valve stem construction for a manipulable valve member used to control fluid flow through a valve. The valve stem extends externally of the valve housing for engagement by a valve handle used to manipulate the valve member between open and closed positions. The valve is formed with a plurality of circumferentially spaced concave splines extending longitudinally on the outer surface of the valve stem. The splines are spaced so as to maximize transmission of rotational torque while minimizing flexure and twisting of the valve stem. The spacing and configuration of the individual splines also ensure a strong mating fit with the valve handle.