Aircraft Landing Gear Spring Coupling for Anti-Rotation Stability

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Solution Overview

Problem

Existing landing gear systems suffer from compass deformation under repeated loading, which can lead to reduced lifespan and instability due to rotational torque, especially in non-steerable and steerable axle configurations.

Innovation Solution

A spring mechanism is integrated into the landing gear, with first and second parts attached to the upper and lower elements respectively, to oppose rotation and create a rotational mechanical coupling, eliminating the need for a compass and providing elastic return torque and force to maintain orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a spring is added to prevent relative rotation between upper and lower members, then control over gear rotation is improved, but device complexity increases

Engineering Contradiction:
Improvecontrol over rotation between upper and lower membersVSAvoidcomplexity of landing gear structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The spring is integrated into the existing telescopic structure of the landing gear, combining the shock absorption function with the new anti-rotation function. The spring is positioned within the telescopic assembly, merging multiple functions into a single structural element rather than adding a separate, complex mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring acts as an intermediary element between the upper and lower members, using elastic deformation to resist relative rotation. This mediator approach allows control over rotation without requiring direct mechanical constraints or complex linkages between the members.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the landing gear structure is reinforced to prevent relative rotation, then stability is improved, but weight increases

Engineering Contradiction:
Improvestability of upper and lower membersVSAvoidweight of landing gear
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

Instead of changing the structural parameters (adding rigid reinforcements), the solution changes the physical state by introducing an elastic element. The spring uses material elasticity to provide rotational control, avoiding the need for heavier rigid structural modifications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces potential mechanical constraint systems (rigid linkages, pins, or structural reinforcements) with an elastic field approach using a spring. This substitution uses the spring's elastic properties to achieve rotational control without the weight penalty of rigid mechanical constraint systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The spring mechanism stabilizes the orientation of the lower element relative to the upper element, reducing the risk of damage and enhancing stability during translational movements, while simplifying the connection between the elements and reducing mass.

Implementation Method 1

a spring opposing rotation between upper and lower members of the landing gear

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4126664B1Aircraft landing gear comprising a spring opposing rotation between upper and lower members of the landing gear
Publication Date: 2026.05.06 SAFRAN LANDING SYSTEMS
  • EP4126664B1 patent drawingFigure 1
  • EP4126664B1 patent drawingFigure 2
  • EP4126664B1 patent drawingFigure 3

AI summary

The invention relates to an aircraft landing gear (0) comprising an upper member (11) intended to be connected with an aircraft structure (2), a lower member (15) carrying an axle (16), the lower member being mounted such that it can move in translation in relation to the upper member along a longitudinal axis (Z-Z), a damper (20) being arranged to dampen translational movements of the lower member (15) relative to the upper member (11). First and second parts (17a, 17b) of a spring (17) are respectively connected to the upper member (11) and to the lower member (15) such that, when the lower member (15) moves in translation relative to the upper member (11), this spring (17) opposes any rotation of the lower member (15) with respect to the upper member (11) about the longitudinal axis (Z-Z).