Glue Joint Cutting Aid for Aircraft Frame Assembly Repair

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Solution Overview

Problem

Existing assemblies between a frame and an additional element, such as a windshield, face challenges in replacing damaged components due to protrusions within the glue joint, which hinder conventional cutting methods and require complex, invasive fastening devices that can cause sealing issues and are not retractable.

Innovation Solution

Incorporating elongated members, such as wires or sheaths, that are partially embedded in the glue joint near protrusions, allowing for cutting assistance by exerting a tensile force on free ends to isolate and remove the glue around protrusions without damaging them, facilitating easier disassembly and replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If protrusions are embedded in the glue joint to resist mechanical and vibratory stresses, then the strength and reliability of the assembly is improved, but the ease of repair deteriorates because conventional cutting methods cannot be used

Engineering Contradiction:

Improveresistance to mechanical and vibratory stressesVSAvoidreplacement of damaged ancillary element

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

A flexible member is preliminarily positioned in the glue joint during assembly, before the need for repair arises. This member is placed in a relaxed state initially, then later tensioned to cut the glue joint when repair is needed, enabling easy removal of the ancillary element without damaging the protrusions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The flexible member acts as an intermediary tool within the glue joint. It mediates between the protrusions (which must remain intact) and the cutting action (which needs to separate the ancillary element). By tensioning this intermediary member, the glue joint is cut while the protrusions are protected from damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of repair

If complex fastening devices with extraction wires are embedded in the glue joint to enable removal, then the ease of repair is improved, but the device complexity increases and sealing problems may occur

Engineering Contradiction:

Improveremoval of ancillary elementVSAvoidfastening devices with extraction wires

Core Design Contradiction:

Ease of repairVSDevice complexity

Solution Approach 1:

The flexible member is extracted from the complex fastening device concept and simplified to be a standalone element that can be independently positioned in the glue joint. It does not require integration with studs or other complex fastening structures, thereby reducing device complexity while maintaining ease of repair.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible member is a simple, inexpensive component that can be easily replaced if needed. Unlike complex fastening devices that require precise positioning and integration, this simple member can be readily installed and used for removal purposes without risking sealing issues.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Strength

If studs are integrated into the frame or ancillary element to provide fastening, then the strength is improved, but the ease of repair deteriorates because the studs cannot be damaged during dismantling

Engineering Contradiction:

Improvefastening capabilityVSAvoidintegrity of integrated studs

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The fastening function is segmented into two independent parts: the protrusions (studs) that provide mechanical strength and fastening capability, and the flexible member that enables removal. This segmentation allows the protrusions to remain intact and undamaged during dismantling, as the flexible member alone performs the cutting action without requiring contact with or damage to the protrusions.

Inventive Principle:

Principle #1Segmentation

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 safe and efficient cutting of glue joints near protrusions, ensuring their integrity and simplifying the replacement process while avoiding invasive procedures and sealing issues, allowing for single-sided maintenance and complete removal of auxiliary elements.

Implementation Method 1

allowing for cutting assistance by exerting a tensile force on free ends to isolate and remove the glue around protrusions

Methodology Applied

Scientific EffectTensile force: Tension

Implementation Method 2

by means in particular of a bonding intermediate such as glue, a seal or a mastic of the aeronautical type called 'PR' based on polysulphide liquid rubber capable of polymerizing at room temperature

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3421350B1Assembly between a frame and an associated element, aircraft comprising such an assembly and methods for securing and releasing such an assembly

Publication Date: 2020.10.07 EUROCOPTER FRANCE SA

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AI summary

The present invention relates to an assembly (1) comprising a chassis (2) having a rim (3), an accessory element (4) attached to said rim (3) of said chassis (2), a glue joint (6) arranged at the interface between a first face (7) of said chassis (2) and a second face (8) of said accessory element (4), and at least one protrusion (9, 10) arranged in said glue joint (6) and forming at least one obstacle to cutting the glue joint (6), said at least one protrusion (9, 10, 19, 20) extending at least partially between said first face (7) of said chassis (2) and said second face (8) of said accessory element (4).