Patent ID: 8534990

Claim:
A variable vane system comprising: a plurality of vanes each being pivotal about an axis; a mechanical linkage for driving said plurality of vanes to rotate about said axis, said mechanical linkage including a ring gear, a plurality of sector gears for rotating, and in turn driving said plurality of vanes to rotate about said axis, and the mechanical linkage including at least one first rod for driving said ring gear to rotate, said first rod driven by a hydraulic servo motor, and the mechanical linkage including a spring bias force, and resisting oscillation; said mechanical linkage includes a hinge knuckle, said first rod causing said hinge knuckle to rotate, to in turn transmit rotation to a second rod, said second rod connected to drive said ring gear, said ring gear configured to rotate, and said spring being a torsional spring to resist torsional oscillation of said ring gear; and said mechanical linkage includes a pivot housing which is configured to pivot about a pin mounted within a fixed housing, said spring including a first end sitting against a portion of said fixed housing, and a second end sitting against a surface on said pivot housing to resist oscillation.