Stator vane linkage

Claim 1

A linkage for imparting circumferential displacement to a stator vane unison ring disposed about a cylindrical compressor case of an axial flow gas turbine engine having an exterior, coaxial fan duct, comprising: a unitary, elongated torque shaft extending radially from the compressor case through the fan duct; a first universal bearing disposed between the torque shaft and the compressor case; a second universal bearing disposed between the fan duct and the torque shaft, including means, slidably receiving the torque shaft therein, for permitting longitudinal displacement between the torque shaft and the second bearing; an internal crank arm, extending laterally from the torque shaft intermediate the first and second universal bearings; a beam, pivotably secured to the compressor case at a pivot point spaced axially from both the unison ring and the second universal bearing; a drive link, disposed between the internal crank arm and the beam for pivoting the beam in response to rotation of the torque shaft; a ring link, extending between the unison ring and the beam and spaced axially from the beam pivot point for driving the unison ring circumferentially in response to the pivoting of the beam; and means, disposed radially outward of the fan duct, for selectably rotating the torque shaft about the longitudinal axis thereof.