Patent ID: 6325326
Filing Date: 2001-12-04
Classification: B64C

Abstract:
A cyclic and collective pitch control device (5) for a helicopter rotor fitted to a drive shaft (2) having a longitudinal axis (A); said device (5) being carried by a fixed supporting element (1) coaxial with said longitudinal axis (A), and comprising:a movable element (12) coaxial with said longitudinal axis (A) and fitted in axially-sliding manner to said supporting element (1), said movable element (12) being substantially sleeve-shaped;a rocking-plate assembly (6) coaxial with said longitudinal axis (A), fitted to said movable element (12) so as to rock, with respect to the movable element, about transverse axes substantially perpendicular to said longitudinal axis (A), and in turn comprising an angularly-fixed first annular element (7), and a second annular element (9) rotating on said first annular element (7) together with said drive shaft (2);supporting and actuating means (17) cooperating with said first annular element (7) to move said rocking-plate assembly (6) and said movable element (12) jointly along said longitudinal axis (A) with respect to said supporting element (1), and to rock said assembly (6), with respect to said movable element (12), about said transverse axes; andconstraint means (18, 20) for preventing angular displacement of said movable element (12), with respect to said supporting element (1), about said longitudinal axis (A);said constraint means comprise prismatic connecting means (18, 20) between said movable element (12) and said supporting element (1); andsaid prismatic connecting means comprise four first flat surfaces (18) arranged in twos parallel to each other which are formed internally on said movable element (12) and equally spaced about said longitudinal axis (A), and cooperate in sliding manner with respective second flat surfaces (20) formed externally on said supporting element (1).