Variable pitch propeller or rotor

Claim 1

A variable pitch multiblade propeller comprising a rotary hub having radial bores, the axes of which are in the same plane and evenly spaced around said hub axis; sleeves of plastic material having a cylindrical and antifrictional inner surface, said sleeves being embedded in said bores and outwardly protruding with respect thereof along a distance at least equal to half their own length; a blade, having a hollow cylindrical root fitted in each of said sleeves for sliding and rotation therein; a lever substantially radial with respect to said root, rigidly secured thereto substantially in the root axis plane for the mean position of the blade, said lever having an inwardly directed pin radial with respect to said hub axis; a ring of plastic material having a rounded periphery coaxially secured to said pin; an elongated radial element capable of torsion about its longitudinal axis axially passing through each said hollow blade rooT and secured to the said hub and to the corresponding blade outwardly with respect to said sleeve; and a rotary plate coaxial to the hub and axially displaceable, said plate having peripheral, axially directed lugs, each lug being provided with a radial cylindrical bore engaging one said plastic ring for sliding, rotating and rocking thereof. 2. A propeller according to claim 1, wherein the diameter of the cylindrical portion of the blade root is greater than the maximum chord of the blade profile.