Abstract: An apparatus for varying the pitch of propulsor blades of a gas-turbine engine by eccentrically driven gears. A first gear is coaxially coupled to one of the propulsor blades whereby angular displacement of the first gear with respect to an engine center-line causes angular displacement of the propulsor blade. A second gear is rotatably coupled to the first gear with one of the first gear and second gear being a first internal gear and the other being a first mating gear. The first internal gear is eccentrically disposed with respect to the first mating gear and has more teeth than does the first mating gear. A third gear is rigidly coupled to the second gear. A fourth gear is rigidly coupled to a rotating structure of the engine and rotatably coupled to the third gear with one of the third gear and fourth gear being a second internal gear and the other being a second mating gear. The second internal gear is eccentrically disposed with respect to the second mating gear.

Abstract: An apparatus for varying the pitch of propulsor blades of a gas turbine engine by eccentrically driven gears. The gas turbine engine includes a rotating structure, an annular gas flowpath coaxial with the rotating structure, a plurality of rotor blades coupled to the rotating structure and extending into the gas flowpath such that a gas stream flowing through the flowpath causes the rotating structure to rotate with respect to the stationary member and a plurality of variable pitch propulsor blades coupled to and disposed radially outwardly of the rotating structure. The pitch of the blade is varied by a pinion gear coaxially coupled to one of the propulsor blades and an internal gear radially disposed about the pinion gear for driving the pinion gear. Annular displacement of the pinion gear causes angular displacement of the propulsor blade with respect to the rotating structure.