Self-Locking Coupling Assembly for Aircraft Conduits

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Solution Overview

Problem

Existing coupling devices for interconnecting conduit members in aircraft face challenges in providing a rigid, lightweight, and misalignment-tolerant connection within constrained spaces, while ensuring fluid tightness and electrical continuity, without the need for additional structural support or bonding springs.

Innovation Solution

A self-locking, self-bonding coupling assembly utilizing a threaded flange, standard flange, and lock nut group with a single o-ring for sealing, and complementary peripheral facing surfaces for snap-fit locking, along with a wave spring for positive engagement, which eliminates the need for external support and ensures electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple sealing members or o-rings are used to provide resiliency for misalignment, then the coupling can tolerate misalignment, but the device complexity and weight increase

Engineering Contradiction:
Improvemisalignment toleranceVSAvoidnumber of sealing members
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent removes bonding springs and multiple sealing members from the coupling assembly, extracting only the essential single o-ring for sealing. This simplification is achieved by designing a rigid coupling that does not require resiliency features, thereby reducing complexity while maintaining misalignment tolerance through precise rigid alignment features.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The coupling assembly is designed to be self-aligning and self-locking without requiring additional bonding springs or multiple sealing members. The rigid structure with integrated alignment features and single o-ring sealing provides misalignment tolerance inherently, eliminating the need for complex resiliency mechanisms.

Inventive Principle:
Principle #25Self-service

2Reliability

If bonding springs are added to ensure coupling remains locked, then the reliability improves, but the device complexity and weight increase

Engineering Contradiction:
Improvelocking reliabilityVSAvoidpresence of bonding springs
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent explicitly removes bonding springs from the coupling assembly, extracting this component to simplify the design. The locking reliability is maintained through a self-locking mechanism with complementary peripheral facing surfaces that provide positive engagement without requiring additional bonding springs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The coupling assembly features self-locking capability through complementary peripheral facing surfaces on the first and second coupling members. These surfaces automatically engage to lock the coupling in place without requiring external bonding springs, thereby maintaining reliability while reducing complexity.

Inventive Principle:
Principle #25Self-service

3Strength

If a rigid connection is provided without misalignment tolerance, then the structural support requirement is reduced, but the coupling cannot accommodate conduit misalignment

Engineering Contradiction:
Improverigid connection strengthVSAvoidmisalignment accommodation
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent applies different functional qualities to different parts of the coupling assembly. The main body provides rigid connection strength for structural support, while specific local features (complementary peripheral facing surfaces and single o-ring positioning) provide controlled misalignment accommodation. This localized approach maintains overall rigidity while allowing necessary adjustments.

Inventive Principle:
Principle #3Local quality

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 coupling assembly provides a reliable, rigid, and leak-proof connection that transmits shear loads, maintains electrical continuity, and fits within constrained spaces, eliminating the need for additional structural support and bonding springs, while ensuring easy installation and maintenance.

Implementation Method 1

a wave spring for biased axial displacement between the lock ring and the nut body

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A self-locking, self-bonding coupling assembly utilizing a threaded flange, standard flange, and lock nut group with a single o-ring for sealing

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP1924800B1Self-locking self-bonding rigid coupling
Publication Date: 2013.07.03 EATON AEROQUIP INC
  • EP1924800B1 patent drawingFigure 1
  • EP1924800B1 patent drawingFigure 2
  • EP1924800B1 patent drawingFigure 3~4

AI summary

A coupling assembly is provided for releasably interconnecting confronting ends of conduit members. The coupling assembly creates a self-locking, and self-bonding connection wherein locking and unlocking is achieved by a predetermined amount of rotation of a lock nut group with respect to a stationary threaded flange. The overall construction of the coupling assembly creates the rigid connection between the conduit members, yet adequate sealing between the conduit members is provided by a single sealing member.