Aircraft Panel Fastener Using Magnetic Studs and Ball Joints

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Solution Overview

Problem

Aircraft panel fixing devices face challenges in being invisible, tolerant to assembly, lightweight, inexpensive, reliable, and compliant with crashworthiness certification regulations, while also needing to dampen vibrations effectively.

Innovation Solution

A reversible fixing assembly with a movable stud and a fixed stud, utilizing a magnetization system with magnets and ball joints for flexible positioning and a crash resistance system with a safety link, allowing for adjustable damping and enhanced structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If screwing means are used to fix the panel, then the fixing device is reliable and inexpensive, but it is visible and offers low mounting tolerances

Engineering Contradiction:
Improvefixing reliabilityVSAvoidvisibility and assembly precision
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical screwing system with a magnetic fixing system. The magnetization means (magnets) provide the fixing force through magnetic attraction between the movable stud on the panel and the fixed stud on the structure, eliminating visible screws and allowing for greater mounting tolerances while maintaining reliability

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

Solution Approach 2:

The patent introduces ball pins as intermediary elements that work in conjunction with the magnetic system. The ball pins engage with receptacles to provide mechanical positioning and support, while the magnetic means provide the primary fixing force, creating a hybrid system that combines the advantages of both magnetic and mechanical fixing methods

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If ball pins or studs with receptacles are used, then the fixing device is less visible and offers better assembly tolerances, but it is expensive and weakly damping vibrations

Engineering Contradiction:
Improvevisibility and assembly toleranceVSAvoidcost and vibration damping
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges magnetic fixing means with ball pin fixing means into a single integrated system. The magnetic means (magnets in movable and fixed studs) provide invisible fixing with good tolerances, while the ball pins provide mechanical support and vibration damping, combining the advantages of both systems while mitigating their individual disadvantages

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fixing device uses a composite approach combining magnetic materials (for invisible fixing and tolerance) with mechanical ball pin elements (for cost-effectiveness and vibration damping). This composite system leverages the strengths of different fixing mechanisms to achieve overall superior performance

Inventive Principle:
Principle #40Composite materials

3Weight of stationary object

If magnets are used for magnetic fixing, then the device is lightweight and offers good assembly tolerances, but the magnet is susceptible to degradation from violent contact and shock

Engineering Contradiction:
Improvefixing device weightVSAvoidmagnet resistance to shock
Core Design Contradiction:
Weight of stationary objectVSReliability

Solution Approach 1:

The patent introduces elastomer members as cushioning elements positioned between the magnetic means and the ball pins/studs. These elastomer members absorb and dampen violent contacts and shocks before they reach the magnets, protecting the magnetic materials from degradation while maintaining the lightweight advantage of the magnetic fixing system

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution provides a reliable, invisible, and tolerant assembly method that is lightweight and cost-effective, while ensuring compliance with crashworthiness regulations and effectively damping vibrations, thereby addressing the panel fixing challenges in aircraft.

Implementation Method 1

at least one magnetization means comprising a magnet

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 2

a first magnetization means cooperating with a second magnetization means of the fixed pad

Methodology Applied
Scientific EffectMagnetic attraction: Magnetic Field

Implementation Method 3

at least one magnetization means is carried by a ball joint of the associated stud

Methodology Applied
Scientific EffectMechanical rotation: Gimbal

Implementation Method 4

at least one elastomer member interposed between a ball joint and a casing of the associated stud

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 5

at least one elastomer member interposed between a ball joint and a casing

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2944751B1A fastener device for fastening a panel to a structure, and an aircraft
Publication Date: 2016.10.19 EUROCOPTER FRANCE SA
  • EP2944751B1 patent drawingFigure 1~12
  • EP2944751B1 patent drawingFigure 2
  • EP2944751B1 patent drawingFigure 3~6

AI summary

The present invention relates to a fastening device (5) provided with at least one movable stud (10) and one fixed stud (100), said movable stud (10) comprising a first magnetization means (15) cooperating with a second magnetization means (115) of said fixed stud (100). At least one magnetizing means (15, 115) is carried by a ball joint (20, 200), each magnetizing means carried by a displacement means (30, 300) which translates the magnetizing means along a longitudinal axis (AX1, AX100) from an engagement position (POS1) to a disengagement position (POS2) in a reversible manner, the magnetizing means (15, 155) being strongly magnetized to each other when they are opposite each other and each in the engagement position (POS1) and not being magnetized or weakly magnetized when at least one magnetizing means (15, 115) is in its disengagement position (POS2).