Pressure Activated Latch for Aircraft Emergency Flotation

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Solution Overview

Problem

Existing emergency flotation systems for aircraft lack a pressure-activated latch that remains closed until a predetermined pressure is applied, leading to undesired inflation and requiring manual operation, and fail to prevent fluid communication between the pressurized source and the inflatable after inflation.

Innovation Solution

A pressure-activated latch with a latch pin and internal biasing element that engages a latching tab to unlock and inflate the emergency door and device sequentially, and returns to a closed position to prevent fluid communication after inflation, using a sealing portion to maintain a fluid seal within the latch housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a manual operation system is used to activate the flotation device, then the system can be controlled by the pilot, but it requires continuous manual intervention and does not provide automatic pressure-activated response

Engineering Contradiction:

Improveautomatic pressure-activated responseVSAvoidmanual intervention requirement

Core Design Contradiction:

Extent of automationVSEase of operation

Solution Approach 1:

The latch pin is designed to automatically respond to pressure changes without requiring manual intervention. The internal biasing element creates a pressure differential that causes the latch pin to slide and disengage the latching tab when predetermined pressure is applied, enabling the system to activate itself based on pressure conditions

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The manual cord-pull mechanism is replaced with a pressure-activated mechanical system. Instead of requiring the pilot to physically pull a cord, the system uses pressure differential across the latch pin to automatically trigger the unlatching and inflation sequence

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the latch remains open after inflation, then the system is simple, but it allows continuous fluid communication between the pressurized source and the inflated device

Engineering Contradiction:

Improvefluid path closure after inflationVSAvoidlatch return mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of requiring an active mechanism to close the latch after inflation, the system uses the pressure differential in reverse. When pressure equalizes after inflation, the internal biasing element reverses the pressure differential, causing the latch pin to automatically slide back and close the fluid path

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If the latch pin is biased to engage the latching tab, then the latch remains closed until predetermined pressure is applied, but the latch must be strong enough to resist pressure until activation

Engineering Contradiction:

Improvelatch closure until activationVSAvoidbiasing force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The biasing element is designed to create a specific pressure differential that corresponds to the predetermined activation pressure. The internal volume and biasing force are calibrated so that the latch pin remains engaged under normal pressure conditions but automatically disengages when the threshold pressure is reached

Inventive Principle:

Principle #35Parameter changes

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

Ensures sequential unlatching and inflation of the emergency door and device, remaining closed until the predetermined pressure is applied, and automatically preventing fluid communication after inflation, enhancing safety and operational efficiency.

Implementation Method 1

an internal biasing element creating a pressure differential causing the latch pin to engage a latching tab

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

A sealing portion creates a slidable fluid seal within the latch housing

Methodology Applied

Scientific EffectFluid sealing:

Data Source

PatentEP1989101B1Pressure activated latch

Publication Date: 2018.01.10 APICAL INDS

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AI summary

A pressure activated latch includes a latch housing, a fluid inlet, a fluid outlet, an internal biasing member and a sliding latch pin that is configured to engage a latch tab that is substantially adjacent to the latch housing. The latch pin is slidable between a first position in which the latch pin prevents fluid communication between the fluid inlet and the fluid outlet and engages the latch tab and a second position in which the latch pin is disengaged from the latch tab and fluid communication is permitted between the fluid inlet and the fluid outlet. The internal biasing member is configured to apply a force upon the latch pin to bias it into the first position.