Variable-pitch impeller for wind turbines defined by a sliding ring

An impeller for wind turbines comprising:

• a rear ring having a central axis;
• a front ring having an inner peripheral surface;
• the front ring being arranged coaxially with respect to the rear ring;
• the front ring being slidably associated with the rear ring and movable along the central axis between a close configuration and a spaced apart configuration with respect to the rear ring;
• a plurality of blades connected to the front ring and defining a variable-pitch propeller, the blades being adjustable between a minimum pitch when the front ring is in the close configuration and a maximum pitch when the front ring is in the spaced apart configuration;
• a shaft extending along the central axis;
• the shaft comprising a rear portion connected to the rear ring and a front portion connected to the front ring;
• the front portion of the shaft being configured to perform a rotational translation movement with respect to the rear portion to switch the front ring between the close configuration and the spaced apart configuration;
• the front portion of the shaft having a front cavity extending along the central axis;
• the rear portion of the shaft being at least partially inserted in the front cavity,
• wherein the front portion comprises at least one spiral guide arranged on an inner surface of the front portion;
• the rear portion comprising at least one slider associated with the spiral guide and arranged on an outer surface of the rear portion.