Turbine Propeller Blade Pitch Locking and Feathering Mechanism

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Solution Overview

Problem

Existing blade pitch control systems for turbine engines are heavy, unreliable, and prone to overspeeding due to the use of counterweights, and they fail to effectively limit propeller blade angles during flight and ground operations, posing safety risks.

Innovation Solution

A purely mechanical device with a movable ring and actuator system that adjusts the stroke length based on the blade's position, allowing for pitch locking and feathering, independent of the primary pitch control system, using a separate energy source and providing a compact, lightweight solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If counterweights are used to generate centrifugal force for feathering blades, then the feathering function is achieved, but the system becomes heavy and complex

Engineering Contradiction:

Improvefeathering functionVSAvoidsystem weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent removes the counterweight component entirely from the system. Instead of using counterweights to generate centrifugal force for feathering, the invention employs a purely mechanical device with a movable ring and actuator system that operates independently of the primary pitch control system, thereby achieving feathering functionality without the excessive weight and complexity of counterweight mechanisms

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the complex mechanical counterweight system with a simplified mechanical device comprising a movable ring, actuator, and stroke control mechanism. This substitution maintains the essential feathering function while dramatically reducing system weight and complexity by eliminating unnecessary mechanical components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Weight of moving object

If the pitch control system is simplified, then weight is reduced, but reliability may be compromised

Engineering Contradiction:

Improvesystem weightVSAvoidsystem reliability

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent incorporates a feathering mechanism that is pre-configured and independent of the primary pitch control system. In the event of primary system failure, this preliminary Feathering capability is immediately available without requiring additional complex backup systems, thereby maintaining reliability while keeping the overall system lightweight

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The movable ring acts as an intermediary component between the actuator and the pitch control mechanism. It provides a simple yet effective means of controlling actuator stroke length to limit blade angles, adding a layer of safety and reliability without introducing complex systems or excessive weight

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If mechanical means are added to limit blade angles, then safety is improved, but device complexity increases

Engineering Contradiction:

ImprovesafetyVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a dynamic movable ring that can change its position along the actuator stroke. This dynamic component allows the system to adaptively limit blade angles during different phases of operation (takeoff, cruise, landing) without requiring multiple fixed mechanical stops or complex control systems, thereby improving safety while maintaining simplicity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The movable ring and actuator system serve multiple functions: they control actuator stroke length, limit blade angles during flight and ground operations, and enable the feathering function. This multi-functionality improves safety without proportionally increasing device complexity, as a single integrated mechanism performs multiple safety-critical tasks

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If an independent feathering system is implemented, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveindependent operationVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the feathering function with the blade angle limiting function into a single integrated mechanism. The movable ring and actuator system that limits blade angles during normal operation also enables feathering when needed, eliminating the need for separate independent feathering systems and thereby improving reliability without proportionally increasing complexity

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10689094B2Device for locking the pitch and for feathering adjustable-pitch fan blades of a turbine engine propeller

Publication Date: 2020.06.23 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A device for locking the pitch and for feathering adjustable-pitch fan blades of a turbine engine propeller, the device including an actuator having at least one movable portion designed to be coupled to pivots of the fan blades of the propeller in order to modify their pitch angle when it slides, a movable part having first mechanical device suitable for co-operating with the actuator when in a fan blade pitch-unlocking position in order to enable the actuator movable portion to slide over an extended actuator stroke; and second mechanical device suitable for co-operating with the actuator when in a fan blade pitch-locking position in order to enable the actuator movable portion to slide over an actuator stroke that is shorter than the extended actuator stroke, and an actuator.