Eccentric Bushing Adjustment Tool for Landing Gear Stay Length

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Solution Overview

Problem

Existing landing gear adjustment tools lack efficient and precise mechanisms for adjusting the stay length during installation, particularly in dual side stay landing gear, where the aft stay length requires fine-tuning.

Innovation Solution

An apparatus comprising an eccentric bushing with circumferentially disposed gear teeth, a secondary bushing, and an adjustment tool with input and output gears, allowing for controlled rotation of the eccentric bushing to displace apertures along its diameter, thereby adjusting the stay length, while a locking key constrains rotation when adjustments are not needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an eccentric bushing is used to adjust stay length, then adjustment capability is improved, but unintended rotation during operation occurs

Engineering Contradiction:
Improveadjustment capabilityVSAvoidunintended rotation prevention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A locking key with gear teeth engages with the gear teeth on the eccentric bushing to prevent unintended rotation during operation. The locking key acts as an intermediary component that selectively constrains the eccentric bushing when adjustment is not required, while allowing free rotation when the locking key is removed or disengaged for adjustment purposes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions between two dynamic states: locked state where the locking key prevents rotation of the eccentric bushing, and unlocked state where the eccentric bushing can rotate freely for adjustment. This dynamic switching between constrained and unconstrained states resolves the contradiction between needing adjustment capability and preventing unintended rotation.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If manual adjustment of eccentric bushing is used, then simplicity is improved, but adjustment precision deteriorates

Engineering Contradiction:
Improveadjustment mechanism simplicityVSAvoidadjustment precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

A gear mechanism serves as an intermediary between the manual input and the eccentric bushing rotation. The gear teeth on the input shaft engage with the gear teeth on the eccentric bushing, providing controlled, precise rotational movement while maintaining overall simplicity of the adjustment mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The gear mechanism provides controlled incremental rotation of the eccentric bushing, allowing precise adjustment through small, manageable rotational steps rather than requiring large manual rotations. This partial action approach enables fine-tuning of the stay length with high precision.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If gear mechanism is added for precise rotation control, then adjustment precision is improved, but device complexity increases

Engineering Contradiction:
Improverotation control precisionVSAvoidmechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The gear mechanism is integrated directly into the existing eccentric bushing structure, with gear teeth formed on the outer surface of the eccentric bushing itself. This merging of the gear function with the eccentric bushing component avoids adding separate complex gearing systems while still providing precise rotation control.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The eccentric bushing serves multiple functions simultaneously: it provides the eccentricity needed for adjustment, contains gear teeth for controlled rotation, and acts as a structural component of the landing gear. This multi-functionality reduces overall device complexity while maintaining adjustment precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables easy, accurate adjustment of the stay length during installation and prevents unintended rotation of the eccentric bushing during normal aircraft operation, ensuring precise and secure positioning of the landing gear.

Implementation Method 1

an input gear having input gear teeth and an output gear having output gear teeth, wherein the input gear teeth and the output gear teeth are in meshed engagement

Methodology Applied
Scientific EffectGear meshing: Gear

Implementation Method 2

rotation of the eccentric bushing causes rotation of the secondary bushing, wherein rotation of the secondary bushing causes the aperture to be displaced along a diameter of the eccentric bushing

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP2927116B1Eccentric tool
Publication Date: 2019.05.01 GOODRICH CORP
  • EP2927116B1 patent drawingFigure 1
  • EP2927116B1 patent drawingFigure 2
  • EP2927116B1 patent drawingFigure 3A

AI summary

An adjustment tool (300) is disclosed herein. For example, an adjustment tool (300) is provided comprising an input gear (302) having gear teeth (316) and an output gear (304) having gear teeth (318), wherein the input gear (302) and the output gear (304) are in meshed engagement, an input shaft (306) centrally coupled to the input gear (302), wherein the input gear (302) is configured to rotate about the input shaft (306), and a housing (312) supporting the input shaft (306) for rotation and supporting a fastener, wherein a tooth (318) of the output gear (304) protrudes from the housing (312).