Self-acting variable pitch vertical axis wind turbine

Abstract

A self-acting variable pitch vertical axis wind turbine is provided with asymmetrically mounted blade paddles rotatably mounted for limited movement such that at one limit of the rotation, a paddle is operational to rotate the impeller and at the other limit of the rotation the paddle feathers.

1 . A self-acting variable pitch vertical axis wind turbine comprising:
 a fixed mounting base defining a centrally positioned bore;   a fixed shaft extending through and secured within the bore;   an electric power generator associated with the fixed shaft and including a rotor rotating about a turbine axis and a stator mounting on the fixed shaft; and   a plurality of blades each having a paddle asymmetrically carried by a spindle, the spindle rotatably mounting on the rotor about a spindle axis.   
   
   
       2 . The wind turbine of  claim 1 , wherein the rotor is formed of a split casing including two complementary top and bottom halves, and the stator is enclosed within the split casing of the rotor, the wind turbine further including:
 a blade mounting for each said blade and formed on the split casing of the rotor, each mounting defining a generally hemi-cylindrical cavity; and   each said spindle carrying thereon a generally quadrant-shaped cam for reception within said cavity and for rotational movement therewithin, the range of relative rotational movement of the blade spindle being limited by the cam and the cavity of the mounting.   
   
   
       3 . The wind turbine of  claim 1 , wherein each paddle defines a paddle plane and wherein each blade is rotatable about the respective spindle axis between first and second blade position, with the paddle plane being substantially parallel to the turbine axis when in the first blade position and with the paddle plane being substantially perpendicular to the turbine axis when in the second blade position. 
   
   
       4 . The wind turbine of  claim 3 , wherein the rotor is formed of a split casing including two complementary top and bottom halves, and the stator is enclosed within the split casing of the rotor, the wind turbine further including:
 a blade mounting for each said blade and formed on the split casing of the rotor, each mounting defining a generally hemi-cylindrical cavity; and   each said spindle carrying thereon a generally quadrant-shaped cam for reception within said cavity and for rotational movement therewithin, the first and second blade positions being limited by the rotational displacement of the cam within the cavity of the mounting.   
   
   
       5 . The wind turbine of  claim 2  wherein the fixed shaft is hollow and at least one power take off cable is accommodated therein. 
   
   
       6 . The wind turbine of  claim 5  wherein the split casing of the rotor is in two halves and each half in combination constitutes the commutator of the generator, whereby rotation of the rotor in use generates power within the stator and the electrical power so generated is conveyed by the said at least one power take off cable. 
   
   
       7 . The wind turbine of  claim 2  wherein the rotor casing is mounted on the fixed shaft through the agency of at least one ball bearing race. 
   
   
       8 . The wind turbine of  claim 2  wherein each half of the rotor casing is provided with at least two mating halves of the blade mountings, each mounting being of aerodynamic shape and orientation. 
   
   
       9 . The wind turbine of  claim 8  wherein five blade mountings are provided equidistantly spaced about the circumference of the casing and mating with its corresponding half such that the spindle of a respective blade is held therewithin in rotatable manner. 
   
   
       10 . The wind turbine of  claim 2  wherein the angular range of movement as between the spindle and blade mountings on the rotor casing is 90°. 
   
   
       11 . The wind turbine of  claim 2  wherein the two halves of the rotor casing are secured together. 
   
   
       12 . The wind turbine of  claim 2  wherein the blade paddles are symmetrically mounted on a respective spindle such that the centre of gravity of each blade is offset from the mid-point of the paddle. 
   
   
       13 . The wind turbine of  claim 2  wherein each spindle is mounted in at least one ball bearing race. 
   
   
       14 . The wind turbine of  claim 2  wherein the blade paddles are of generally rectangular form. 
   
   
       15 . The wind turbine of  claim 2  wherein the blade paddles are of curved form. 
   
   
       16 . The wind turbine of  claim 2  wherein the surfaces of the blade paddles are provided with embellishments. 
   
   
       17 . The wind turbine of  claim 16  wherein the embellishments are in the form of contours associated with a particular activity or interest. 
   
   
       18 . A self-acting variable pitch vertical axis wind turbine comprising:
 a fixed mounting base defining a centrally positioned bore;   a fixed shaft extending through and secured within the bore;   an electric power generator associated with the fixed shaft and including a rotor and a stator;   the rotor being formed of a split casing including two complementary top and bottom halves;   the stator being mounted on the fixed shaft and enclosed within the split casing of the rotor;   blade mountings formed on the split casing of the rotor, each mounting defining a generally hemi-cylindrical cavity; and   a blade for each blade mounting, including a spindle carrying thereon a generally quadrant-shaped cam for reception within the said cavity and for rotational movement therewithin, and a paddle asymmetrically carried by the spindle, the range of relative rotational movement of the blade spindle being limited by the cam and the cavity of the mounting, whereby in use in one position at one limit of the range the blade paddle is operational to rotate the rotor and at the other limit of the range the blade paddle feathers.