Methods and apparatus for controlling variable stator vanes

A compressor comprising:

• a variable stator vane assembly comprising:
• a plurality of variable stator vanes pivotally mounted in a casing of said compressor for rotation about a stator vane axis;
• a plurality of levers each having a proximal end and an opposite distal end, each of said proximal ends fixedly coupled to a corresponding stator vane of said plurality of variable stator vanes for pivoting said corresponding stator vane about said stator vane axis;
• an actuation ring coaxially surrounding said compressor casing adjacent said plurality of levers, said actuation ring coupled to said distal ends of each of said plurality of levers for pivoting said levers as said actuation ring is rotated about a compressor rotation axis, said actuation ring comprising a pin extending outward from a radially outward surface of said actuation ring, said pin rotatably coupled to said actuation ring;
• and
• a template comprising a slot for receiving at least a portion of said pin, an inner surface of said slot interacts with an outer surface of said in to convert rotational motion of said pin into translation of said pin in said slot, said slot comprising a shape configured to guide rotation of said actuation ring about said compressor rotation axis when said template is moved relative to said actuation ring.

An actuation system for a plurality of variable stator vanes pivotally mounted in a casing of a compressor, said system comprising:

• a plurality of levers each having a proximal end and an opposite distal end, each of said proximal ends fixedly coupled to a corresponding stator vane of the plurality of variable stator vanes for pivoting the corresponding stator vane about a stator vane axis;
• a template comprising a pin extending inward from a radially inward surface of said template, said pin rotatably coupled to said template;
• and
• an actuation ring coaxially surrounding the casing adjacent said plurality of levers, said actuation ring coupled to said distal ends of each of said plurality of levers for pivoting said levers as said actuation ring is rotated about a compressor rotation axis, said actuation ring comprising a slot for receiving at least a portion of said pin, an inner surface of said slot interacts with an outer surface of said in to convert rotational motion of said pin into translation of said pin in said slot, said slot comprising a shape configured to guide rotation of said actuation ring about said compressor rotation axis when said template is moved relative to said actuation ring.