Rotor shaft with internal controls for helicopters

Claim 1

A rotor shaft and hub assembly for helicopters comprising: a rotatable outer shaft assembly including a main tubular shaft and a blade support hub coupled therewith, and arranged in a substantially vertical position, said main shaft having an upper end and a lower end, an axial bore being at the uuper end of the main shaft, the lower end of the main shaft adapted to be rotatably driven, the blade support hub being between the upper end and the lower end of the main shaft; a fixed inner shaft arranged within said outer shaft assembly and co-axial therewith, the upper end of the inner shaft being disposed in the bore, the upper end of the main shaft being rotatably coupled with the upper end of said inner shaft; a plurality of kinematic linkages coupled with the main shaft and extending therethrough and each adapted to be connected to a respective blade to control the pitch thereof; a swivel plate assembly arranged within said outer shaft assembly and supported thereby, said swivel plate assembly being connected to said kinematic linkages and being coupled to the outer surface of said inner shaft to slide axially therealong; and a plurality of actuator means extending along said inner shaft inside the space lying between said main shaft and said inner shaft, and connected to said swivel plate assembly to control the cyclic and collective pitch of said blades; whereby the main shaft serves to protect the actuator means, the swivel plate assembly and part of the kinematic linkages.