Foldable blade for a wind turbine and method of use

A wind turbine configured for extracting energy from a fluid flow, the wind turbine comprising a rotor, the rotor comprising:

• a rotatable hub;
• a plurality of foldable rotor blades coupled to the hub and rotatable about a horizontal rotor axis, where each of the plurality of foldable rotor blades has a single fixed rotation point at a blade root;
• and
• a mechanical actuation structure coupled to the plurality of foldable rotor blades, wherein the mechanical actuation structure moves the plurality of foldable rotor blades to a deployed state, substantially perpendicular to the horizontal rotor axis, to capture kinetic energy from an incoming fluid flow and moves the plurality of foldable rotor blades to a non-deployed state, substantially parallel to the horizontal rotor axis, the mechanical actuation structure comprising:
• a plurality of toothed wheels, each of the plurality of foldable rotor blades coupled to one of the plurality of toothed wheels at the single fixed rotation point and rotatable in response to an incoming fluid flow,
• a threaded rod disposed in cooperative engagement with each of the plurality of toothed wheels;
• and
• a spring disposed proximate the threaded rod and configured to compensate for the static wind load on each of the plurality of foldable rotor blades,
• wherein rotation of each of the plurality of toothed wheels applies a force on the threaded rod in a direction opposed to the incoming fluid flow and compression of the spring by the threaded rod.

A method of using of a wind turbine comprising:

• providing a wind turbine including a hub and a plurality of foldable rotor blades coupled to the hub and rotatable about a horizontal rotor axis, where each of the plurality of foldable rotor blades has a single fixed rotation point at a blade root;
• rotating the at least one rotor blade about the horizontal rotor axis to generate energy;
• determining if incoming fluid flow exceeds a rated value;
• actuating a mechanical actuation structure coupled to each of the plurality of foldable rotor blades in the presence of an incoming fluid flow that exceeds the rated value to move the plurality of foldable rotor blades to a non-deployed state, substantially parallel to the horizontal rotor axis;
• determining if the incoming fluid flow exceeds the rated value;
• actuating the mechanical actuation structure in the presence of an incoming fluid flow that does not exceed the rated value to move the plurality of foldable rotor blades to a deployed state, substantially perpendicular to the horizontal rotor axis, to capture kinetic energy from the incoming fluid flow that is within the rated value,
• wherein the mechanical actuation structure comprises:
• a plurality of toothed wheels, each of the plurality of foldable rotor blades coupled to one of the plurality of toothed wheels at the single fixed rotation point,
• a threaded rod disposed in cooperative engagement with each of the plurality of toothed wheels;
• and
• a spring disposed proximate the threaded rod and configured to compensate for a static wind load on each of the plurality of foldable rotor blades.