US Patent 8997591 Control knob return/detent mechanism

An encoder assembly including control knob return mechanisms and encoder elements. Each control knob return mechanism includes a frame assembly including return spring locators. A return rotor assembly, includes a rotor having a plurality of rotor located spring stops. A return mechanism rotatable shaft is operably positioned within the return rotor assembly and operably connectable to an encoder element. The rotor and the shaft are rotatably stationary relative to each other. A return spring is positioned about the rotatable shaft and operably positioned relative to the return spring locators and the rotor located spring stops to bias the return mechanism rotatable shaft and the rotor in a normally centered position. Each encoder element is connected to an associated return mechanism rotatable shaft of an associated control knob return mechanism, wherein the return mechanism rotatable shafts of the control knob return mechanisms are concentrically positioned relative to each other.