Continuous-Cable Switch Fuse for Heat-Free Aircraft Protection

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Solution Overview

Problem

Existing circuit breakers for electrical cables generate thermal heating due to electrical connections and have a risk of unexpected disconnection, leading to oversizing and increased onboard mass, particularly in aircraft applications.

Innovation Solution

A circuit breaker design featuring a linking system that forms a continuous tube around the electrical cable, eliminating electrical connections and incorporating a movable knife for seamless disconnection, with a pyrotechnic control for rapid activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If removable electrical connections are used to connect the conductive bar to the cable sections, then the device can be quickly replaced, but local heating is generated by the Joule effect and the connections may disconnect unexpectedly

Engineering Contradiction:
Improvereplaceability of the deviceVSAvoidconnection stability
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The invention extracts and eliminates the electrical connections from the system. Instead of using removable connectors that heat up and may disconnect, the patent uses a continuous conductive bar that passes through the protection device and directly connects the cable sections, removing the problematic connection points while maintaining replaceability of the protection device itself.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of repair

If removable electrical connections are used to connect the conductive bar to the cable sections, then the device can be quickly replaced, but the on-board mass increases due to oversizing of components

Engineering Contradiction:
Improvereplaceability of the deviceVSAvoidon-board mass
Core Design Contradiction:
Ease of repairVSWeight of moving object

Solution Approach 1:

By removing the electrical connections entirely and using a continuous conductive bar, the patent eliminates the need for oversized connectors and associated cooling components, thereby reducing the overall mass of the protection device while maintaining full replaceability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a continuous electrical cable is used without removable connections, then thermal heating and disconnection risks are eliminated, but the device cannot be quickly replaced

Engineering Contradiction:
Improveconnection stabilityVSAvoidreplaceability of the device
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The invention segments the protection device from the cable system. The conductive bar remains continuous and permanently connected to the cable sections, while the protection device (housing with sectioning system) is made replaceable as a separate unit, achieving both reliability and ease of repair.

Inventive Principle:
Principle #1Segmentation

4Extent of automation

If electrical connections are used to transmit signals for triggering the pyrotechnic charge, then the sectioning system can be activated, but additional connection points increase heating and disconnection risks

Engineering Contradiction:
Improveactivation of sectioning systemVSAvoidconnection stability
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The invention extracts and eliminates the signal transmission connections from the system. Instead of using electrical connections to trigger the pyrotechnic charge, the patent uses a mechanical triggering mechanism where the conductive bar itself activates the sectioning system through direct mechanical interaction, removing additional connection points and their associated risks.

Inventive Principle:
Principle #2Taking out (Extraction)

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 prevents thermal heating and disconnection risks, reducing the need for oversized components and ensuring reliable, rapid cable severance without generating heat, suitable for high-power aircraft electrical circuits.

Implementation Method 1

The control 22 is a pyrotechnic charge which is triggered upon receipt of an electrical signal transmitted by an electrical cable 24

Methodology Applied
Scientific EffectPyrotechnic charge: Combustion

Implementation Method 2

the first and second electrical connections 26.1, 26.2 generate local heating by Joule effect

Methodology Applied
Scientific EffectJoule effect: Joule Heating

Data Source

PatentEP4358108B1Electrical protection device of the switch fuse type positionable on a continuous electrical cable and aircraft comprising the same
Publication Date: 2026.04.15 AIRBUS OPERATIONS (SAS)
  • EP4358108B1 patent drawingFigure 1~3

AI summary

The invention relates to an electrical protection device of the circuit breaker type comprising a housing (34), a disconnecting system (38) positioned within the housing (34), configured to occupy inactive and active states corresponding respectively to the conducting and non-conducting states of the electrical protection device (32), and a connecting system (36) configured to occupy an open state in which it allows the insertion of an electrical cable (30) and a closed state in which it surrounds the electrical cable (30). The connecting system (36) and the disconnecting system (38) are arranged such that, when the connecting system (36) is in the closed state, the disconnecting system (38) cuts the electrical cable (30) during a transition from the inactive to the active state. This solution allows for a continuous electrical cable. In the absence of an electrical connection, the risks of overheating and disconnection are eliminated.