Patent ID: 8757975
Filing Date: 2014-06-24
Classification: B64C,B64D,Y02T

Abstract:
1. A pitch control mechanism for controlling the pitch of propellers of a propeller assembly, the pitch control mechanism having: a hydraulic actuator which has first and second hydraulic cylinders, each hydraulic cylinder being operable to angularly displace the propellers of the propeller assembly between fine and coarse positions, one or more main hydraulic fluid supply lines which are connected to the first and second hydraulic cylinders to supply fluid via the main hydraulic fluid supply lines to operate the hydraulic cylinders, one or more first back-up hydraulic fluid supply lines which are connected to the first hydraulic cylinder to supply fluid via the first back-up hydraulic fluid supply lines to the first hydraulic cylinder to displace the propellers to a coarser position, and one or more second back-up hydraulic fluid supply lines which are connected to the second hydraulic cylinder to supply fluid via the second back-up hydraulic fluid supply lines to the second hydraulic cylinder to displace the propellers to a coarser position; wherein, in the event of inadequate supply of fluid by the main hydraulic fluid supply lines, the first and/or the second back-up hydraulic fluid supply lines can supply fluid to the respective hydraulic cylinders to displace the propellers to a coarser position.