Variable-Pitch Propeller Hydraulic Control Against Reverse Thrust Failure

The patent applies preliminary anti-action by incorporating a mechanically actuated pressure reducing means that automatically counteracts the basic pressure from the pressure generating device when the servo valve fails. This mechanical counter-action prevents the propeller blades from being unintentionally adjusted to reverse thrust position by preemptively reducing control pressure when failure conditions are detected through increased rotation speed or centrifugal force.

The patent uses an intermediary mechanical pressure reducing means (such as an overspeed governor or centrifugal governor) that acts as a mediator between the pressure generating device and the propeller pitch control system. This intermediary device mechanically reduces the control pressure when the servo valve fails, preventing direct transmission of basic pressure to the propeller blades and thus blocking unintended reverse thrust adjustment.

The patent applies self-service by designing the pressure reducing means to be automatically actuated by the system's own operating parameters (rotation speed, centrifugal force) without requiring external control signals or additional sensors. The mechanically actuated device self-regulates by using the kinetic energy and centrifugal effects already present in the rotating propeller system to reduce control pressure when failure conditions occur, eliminating the need for complex electronic monitoring and control systems.

The patent replaces complex electronic control systems with a simple mechanically actuated pressure reducing means that uses purely mechanical principles (centrifugal force, overspeed governor mechanics) to detect failure conditions and respond. This mechanical substitution eliminates the need for electronic sensors, control algorithms, and power systems, reducing overall device complexity while maintaining safety functionality.