Fail-Safe Sliding Arm Assembly for Aircraft Doors

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional sliding closing elements in vehicles, such as aircraft, are prone to loss due to failure of bogie support arms under high aerodynamic forces, leading to increased weight and cost due to over-dimensioning for safety, and pose safety risks if detached during flight.

Innovation Solution

A fail-safe sliding arm assembly with a bogie support arm and a safety arm that retains the sliding closing element on the rail in case of failure, using a lightweight bogie support arm and a safety arm that grips the rail on both sides, reducing weight and manufacturing costs while ensuring safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bogie support arm is made heavier and over-dimensioned to resist high aerodynamic forces, then the reliability and safety of the sliding closing element is improved, but the weight of the bogie support arm increases significantly

Engineering Contradiction:

ImprovereliabilityVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The bogie support arm is divided into two separate arms: a primary bogie support arm that carries the bogie assembly and a safety arm that provides backup support. This segmentation allows each arm to be optimized for its specific function, with the safety arm being lighter than a fully over-dimensioned single arm would be, while maintaining overall system reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The safety arm acts as a pre-positioned backup support that engages automatically if the primary bogie support arm fails. This beforehand cushioning ensures that the sliding closing element remains supported even upon failure of the primary arm, preventing loss during flight without requiring the primary arm to be over-dimensioned for worst-case scenarios.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the bogie support arm is over-dimensioned to ensure safety under all flight conditions, then the reliability is improved, but the manufacturing cost increases due to expensive machining elements

Engineering Contradiction:

ImprovereliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By segmenting the support function into a primary bogie support arm and a separate safety arm, each component can be manufactured to its minimum necessary dimensions rather than requiring the entire structure to be over-dimensioned. This reduces material costs and machining complexity while maintaining the required safety level.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The safety arm can be designed as a simpler, lighter component that serves as a backup. If the primary arm fails, the safety arm provides support, allowing the use of more cost-effective materials and manufacturing processes for the safety arm compared to a fully over-dimensioned primary arm.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If a conventional single bogie support arm is used, then the device complexity is low, but the risk of losing the sliding closing element during flight increases in case of failure

Engineering Contradiction:

Improvedevice complexityVSAvoidsafety

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The support function is segmented into a primary bogie support arm and a safety arm, creating a redundant system. This segmentation increases device complexity only minimally while dramatically improving safety by ensuring that failure of one arm does not result in loss of the sliding closing element.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The safety arm is pre-positioned and designed to engage automatically upon failure of the primary bogie support arm. This beforehand cushioning provides immediate backup support without requiring complex control systems or additional mechanisms, thus improving safety with minimal increase in device complexity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS10066430B2Sliding closing element, in particular a sliding door or a sliding window, for a sliding closing element arrangement of a vehicle, in particular of an aircraft

Publication Date: 2018.09.04 AIRBUS HELICOPTERS DEUT GMBH

AI summary

A sliding closing element for a sliding closing element arrangement of a vehicle, the sliding closing element arrangement comprising at least one rail that is adapted for slidably supporting the sliding closing element, the sliding closing element comprising at least one fail safe sliding arm assembly with at least one bogie support arm and at least one safety arm, the at least one bogie support arm comprising at least one bogie assembly with at least one guide roller that is adapted for rolling along the at least one rail in operation, and the at least one safety arm being adapted for retaining the at least one fail safe sliding arm assembly on the at least one rail in case of a failure of the at least one bogie support arm.