Aircraft Return Lever Phase Shift to Eliminate Moving Harness Weight

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Solution Overview

Problem

Existing aircraft control systems face issues with the weight and balance caused by the movement of series actuators and electrical harnesses in mechanical flight control chains, leading to unbalanced mass distribution and increased complexity.

Innovation Solution

A return device with an upstream and downstream lever system, utilizing a phase shift mechanism and a linear actuator that allows rotation without translation, eliminating the need for a moving electrical harness and compensation masses, and integrating both stabilization and trim functions within a single device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a series actuator is integrated into the mechanical flight control chain, then stabilization function is achieved, but the electrical harness must be maximized in length to tolerate movement, generating excess weight

Engineering Contradiction:
Improvestabilization functionVSAvoidelectrical harness weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The invention divides the control system into two independent parts: a stationary actuator mounted on the aircraft structure and a movable control chain. This segmentation allows the electrical harness to remain short and fixed while the mechanical control elements move independently, eliminating the need for an oversized flexible harness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a stationary actuator as an intermediary element that converts electrical commands into mechanical movements externally to the control chain. This mediator transfers the stabilization function without requiring the electrical harness to follow the moving parts, thus reducing harness weight and complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a series actuator moves in translation, then stabilization is achieved, but mass compensation members are required, increasing device complexity

Engineering Contradiction:
ImprovestabilizationVSAvoidmass compensation members
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of moving the actuator with the control chain (traditional approach), the invention inverts the arrangement by mounting the actuator stationary on the aircraft structure and allowing the control chain to move independently. This eliminates the need for mass compensation since the actuator remains fixed.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention creates a separate mechanical pathway for control signals that does not require the actuator to physically move with the control elements. The stationary actuator generates forces that are transmitted through fixed mechanical linkages, copying the effect of movement without actual movement of the actuator itself.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If the electrical harness is made flexible to allow deformation, then movement tolerance is achieved, but excess weight is generated

Engineering Contradiction:
Improvemovement toleranceVSAvoidelectrical harness weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The invention extracts the movement function from the electrical harness by separating the electrical connection system from the mechanical control chain. The harness remains short and stationary while the control elements move independently, eliminating the need for heavy flexible materials.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration simplifies the integration of series actuators in aircraft control systems, reducing weight and complexity by eliminating the need for translation movement and compensation masses, while maintaining transparent operation for pilots.

Implementation Method 1

said output rod being connected by a helical connection of output to the downstream lever so that a translation of the output rod generates a rotation of the downstream lever around said axis of rotation with respect to the upstream lever

Methodology Applied
Scientific EffectHelical connection: Screw

Data Source

PatentEP3702278B1Device for assisted transmission and aircraft
Publication Date: 2021.05.19 EUROCOPTER FRANCE SA
  • EP3702278B1 patent drawingFigure 1~2
  • EP3702278B1 patent drawingFigure 3~4

AI summary

The present invention relates to a return device (1) equipped with an upstream lever (2) and a downstream lever (6). The return device (1) includes a phase-shifting system (10) connected to the upstream lever (2) and the downstream lever (6) such that a rotation of the upstream lever (2) around an axis of rotation (AX) induces a rotation of the downstream lever (6) around this axis of rotation (AX), the phase-shifting system (10) comprising a linear actuator (15) carried by the upstream lever (2), said linear actuator (15) having an output rod (20), said output rod (20) having only one degree of freedom in translation with respect to the upstream lever, said output rod (20) being connected by an output helical link (21) to the downstream lever (6) so that a translation of the output rod (20) generates a rotation of the downstream lever (6) around said axis of rotation (AX).