Rotor Blade Folding Locking at the Mast Axis

Solution Overview

Problem

Conventional rotor blade folding mechanisms in tiltrotor aircraft require excessive components and are located far from the mast axis, generating undesirable forces at high speeds, limiting forward speed and range.

Innovation Solution

A blade position control system (BPCS) that allows rotor blades to pivot about a pitch axis and fold using a centralized mechanism with a single linkage path, reducing complexity and minimizing drag by locking blades in extended positions and allowing folding, thus enabling efficient transition between flight modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional rotor blade folding mechanisms are used, then blade folding capability is achieved, but device complexity increases excessively and components are disposed far from mast axis generating undesirable forces

Engineering Contradiction:

Improveblade folding capabilityVSAvoidactuation and locking systems complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the folding actuation and locking functions into a single integrated mechanism located at the mast axis. The actuator directly drives a locking mechanism that performs both folding and locking operations, eliminating the need for separate actuation and locking systems. This merging of functions reduces device complexity while maintaining blade folding capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent repositions the folding mechanism components from a location far from the mast axis to the mast axis itself. This dimensional repositioning changes the mechanical advantage and force distribution, eliminating undesirable forces generated by offset components. The mechanism operates in a different spatial configuration that resolves the force generation problem while maintaining folding functionality.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If conventional rotor blade folding mechanisms with components far from mast axis are used, then blade folding is enabled, but undesirable forces are generated at high speeds

Engineering Contradiction:

Improveblade folding capabilityVSAvoidundesirable forces at high speeds

Core Design Contradiction:

Adaptability or versatilityVSForce

Solution Approach 1:

The patent repositions the folding mechanism components from a location far from the mast axis to the mast axis itself. This dimensional repositioning changes the mechanical advantage and force distribution, eliminating undesirable forces generated by offset components. The mechanism operates in a different spatial configuration that resolves the force generation problem while maintaining folding functionality.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent designs the locking mechanism to counterbalance forces during blade folding operations. The mechanism includes force-balancing elements that offset the undesirable forces generated during high-speed rotation, allowing smooth folding operations without generating harmful lateral or radial forces on the mast structure.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Speed

If rotor blades are locked in extended positions, then forward speed and range are improved, but blade position control complexity increases

Engineering Contradiction:

Improveforward speedVSAvoidblade position control complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent combines the folding actuation and locking functions into a single integrated mechanism located at the mast axis. The actuator directly drives a locking mechanism that performs both folding and locking operations, eliminating the need for separate actuation and locking systems. This merging of functions reduces device complexity while maintaining blade folding capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The locking mechanism is designed to automatically engage and lock the rotor blades in the extended position through its own mechanical action during the folding cycle. The mechanism uses the motion of the actuator itself to drive the locking engagement, eliminating the need for separate locking actuators or complex control systems. The system serves its own locking function through its primary actuation motion.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12589868B2Blade position control system

Publication Date: 2026.03.31 TEXTRON INNOVATIONS INC

AI summary

An aircraft that has a blade position control system (BPCS). The BPCS includes an actuator, a multilobe component configured for at least one of longitudinal movement along a mast axis as a function of actuation of the actuator and rotational movement relative to the mast axis as a function of actuation of the actuator. Movement of the multilobe component selectively restricts at least one of pitch movement and folding of a plurality of rotor blades.