Rotor hubs on rotary wing aircraft

Claim 1

A rotor for rotary-wing aircraft, said rotor being limited to articulation in flap and pitch modes wherein drag movements induced in flight by the flapping of rotor blades connected to the rotor are elastically facilitated responsive to the flexibility of the rotor blades in their planes; said rotor comprising a hollow one-piece hub and rotor mast, the rotor being characterized by said rotor mast having its upper end portion widening into a sealed chamber forming said hub, blade attachment members integrally formed with said hub and extending outwardly thereof, said attachment members being adapted to receive the interconnecting means of said rotor blades, said attachment members comprising spaced double lobes disposed in planes parallel to the rotational axis of said rotor, said double lobes forming yokes equal in number to the number of said rotor blades, the ends of said interconnecting means received in said yokes being shaped to constitute flapping hinges and being formed by shoulder portions of a stub-axle member upon which a sleeve comprising a blade attachment is rotatably restrained, antifriction thrust bearings and anti-friction pivotal-motion bearings being located in pairs in cap members urged together from the exterior through the bores of said lobes, the ends of the shoulder portions being included between said bearings, and a spacer member extending through said shoulder portions, said cap members being in turn clamped from the exterior by internal abutment against the ends of said spacer member.