US Patent 7798442 Rotor assemblies having automatic blade folding systems

A rotor assembly having a rotor hub, a plurality of yokes, and a plurality of swing arms is provided. The yoke depending from the rotor hub. Each swing arm is movably positioned on the rotor hub for rotation between an unlocked position and a locked position. The yokes are freely movable about a pitch axis and a lead/lag axis when the swing arms are in the unlocked position and the yokes are locked in a predetermined pitch position and a predetermined lead/lag position when the swing arms are in the locked position.