Patent ID: 8757976
Filing Date: 2014-06-24
Classification: B64C,B64D

Abstract:
1. A pitch control mechanism for angular displacement of propellers of a propeller assembly of an engine arrangement, the pitch control mechanism having: an epicyclic gear system rotating with the propeller assembly and comprising a sun gear, one or more planet gears engaging the sun gear, a ring gear engaging the planet gears, and a planet carrier carrying the planet gears, one of the sun gear, the ring gear and the planet carrier being a first input to the epicyclic gear system, another of the sun gear, the ring gear and the planet carrier being a second input to the epicyclic gear system, and the last of the sun gear, the ring gear and the planet carrier being an output from the epicyclic gear system, a drive gear located on a static structure of the engine arrangement, and controlling the rotational speed of the first epicyclic input in the rotating frame of reference of the propeller assembly, a control gear located on a static structure of the engine arrangement, and controlling the rotational speed of the second epicyclic input in the rotating frame of reference of the propeller assembly, and a drive mechanism rotating with the propeller assembly, the drive mechanism accepting rotary motion from the epicyclic output to deliver an output motion which angularly displaces the propellers of the propeller assembly; wherein varying a rotation of at least one of the drive gear and the control gear varies the direction of rotation of the epicyclic output, and thereby changes the output motion delivered by the drive mechanism to control the angular displacement of the propellers of the propeller assembly.