Aircraft Repair Patch Tool for Uniform Heat and Pressure

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for applying repair patches to aircraft component coatings, particularly on complex surfaces like the leading edges of fan inlet cases, are inefficient due to the difficulty in applying uniform heat and pressure, often requiring expensive autoclaves and lengthy offsite repairs.

Innovation Solution

A repair tool comprising a heating element, a flexible bladder, and an inflexible shell, controlled by a controller, which applies consistent pressure and heat to match the curvature of the surface, allowing for on-site repairs of erosion-resistant coatings by inflating the bladder to maintain pressure and using a flexible heating element to maintain temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional autoclave methods are used to apply repair patches, then uniform heat and pressure can be achieved, but repair time increases and costs increase due to offsite repairs

Engineering Contradiction:
Improveuniformity of heat and pressure applicationVSAvoidrepair time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent employs a flexible bladder made of elastomeric material that can be inflated to conform to complex curved surfaces of aircraft components. This flexible shell structure enables the application of uniform pressure distribution across irregular geometries, eliminating the need for rigid autoclave equipment while allowing on-site repairs. The flexible nature of the bladder permits adaptation to various surface shapes without requiring component removal or specialized facilities.

Inventive Principle:
Principle #30Flexible shells and thin films

2Stress or pressure

If traditional rigid pressure application methods are used, then sufficient pressure can be applied to complex surfaces, but the equipment becomes too large and expensive for on-site repairs

Engineering Contradiction:
Improvepressure applied to patchVSAvoidequipment size and cost
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The patent utilizes pneumatic inflation of an elastomeric bladder to generate and apply pressure to the repair patch. By inflating the bladder with compressed air or gas, sufficient pressure is achieved to bond the patch to the component surface. This pneumatic approach replaces heavy rigid mechanical press systems with a lightweight, portable inflatable structure, dramatically reducing equipment size and cost while enabling on-site repair operations.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the physical state and properties of the pressure application medium from rigid solid contact to inflatable gas-filled elastomeric structure. This parameter change allows the pressure application device to transition from a fixed, heavy autoclave system to a flexible, portable inflatable bladder that can adapt its shape and pressure distribution to match complex component geometries, reducing both equipment complexity and cost.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If heating is applied to complex curved surfaces, then patch adhesion is improved, but uniform temperature distribution becomes difficult to achieve

Engineering Contradiction:
Improvepatch adhesionVSAvoiduniformity of temperature distribution
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs a flexible heating element that can be conformally attached to complex curved surfaces. This flexible thermal transfer medium distributes heat uniformly across irregular geometries by conforming to the surface shape, ensuring consistent temperature distribution throughout the patch application area. The flexibility of the heating element allows it to maintain intimate contact with the component surface, improving thermal coupling and adhesion while achieving uniform temperature distribution.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If repair patches are applied to high-wear locations with complex geometries, then erosion protection is improved, but the application process becomes more difficult

Engineering Contradiction:
Improveerosion protectionVSAvoiddifficulty of patch application
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs flexible inflatable bladders and conformable heating elements that can be easily positioned and inflated to match complex curved surfaces at high-wear locations such as leading edges. This flexibility dramatically simplifies the application process compared to rigid autoclave methods, as the inflatable bladder can be manually positioned and inflated on-site without requiring component removal or specialized facilities, making erosion protection application straightforward even on difficult geometries.

Inventive Principle:
Principle #30Flexible shells and thin films

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 efficient and on-site application of repair patches with uniform heat and pressure, reducing repair time and costs by accommodating complex surface geometries, ensuring effective adhesion and integration of patches on high-wear areas.

Implementation Method 1

a flexible bladder and an inflexible shell, the flexible bladder configured to apply pressure to the coating patch and the heating element

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

a heating element, a flexible bladder, and an inflexible shell, the flexible bladder configured to apply pressure to the coating patch and the heating element

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3409456B1Aircraft repair patch application tool
Publication Date: 2023.07.05 RTX CORP
  • EP3409456B1 patent drawingFigure 1~2
  • EP3409456B1 patent drawingFigure 3
  • EP3409456B1 patent drawingFigure 4~6

AI summary

A repair tool (400) for applying a coating patch (404) includes a heating element (410), a flexible bladder (420) disposed adjacent the heating element (410), and an inflexible shell (430) disposed about the flexible bladder (420). The inflexible shell (430) defines a negative space (434) corresponding to a plurality of sides of an aircraft component. A controller (440) is communicatively coupled to the heating element (410) and the bladder (420), and is configured to control a temperature of the heating element (410) and a pressure of the flexible bladder (420).