Rotary-Handle Latch with Electrical Feedback for Aircraft Doors

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Solution Overview

Problem

Existing latching assemblies for aircraft compartments fail to securely maintain access doors in flight and provide reliable closure indications, lacking a mechanism to indicate whether the door is securely closed or not.

Innovation Solution

A rotary-handle latch system with a base, swivel arm, rotary arm assembly, handle mechanism, slide plate, bolt assembly, and plunger assembly, which includes an electrical switch to provide signals indicating locked or unlocked positions, ensuring secure closure and easy operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional latching assembly is used, then the structure is simple, but it fails to provide reliable indication of door closure status

Engineering Contradiction:
Improvedoor closure indication reliabilityVSAvoidlatch structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback through electrical switches (microswitches) that detect the position of the handle and plunger assembly, providing real-time indication of door closure status to the flight deck. This resolves the contradiction by adding reliable feedback without significantly complicating the mechanical latching structure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses electrical switches as intermediaries between the mechanical latching components and the indication system. These switches translate mechanical positions into electrical signals, enabling reliable status indication while keeping the mechanical structure relatively simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the latch uses a complex mechanism to ensure secure closure, then reliability improves, but ease of operation deteriorates

Engineering Contradiction:
Improvedoor securing reliabilityVSAvoidhandle operation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs a dynamic handle mechanism that can be rotated to different positions (open, closed, locked) and a plunger assembly that automatically moves to engage or disengage switches. This dynamic design maintains ease of operation through simple rotational motion while ensuring reliable closure through automatic engagement mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The plunger assembly automatically moves to engage or disengage electrical switches based on handle position, without requiring additional manual intervention. This self-service mechanism ensures reliable status indication while keeping the operation simple for the user.

Inventive Principle:
Principle #25Self-service

3Loss of information

If the latch provides detailed status indication, then information availability improves, but device complexity increases

Engineering Contradiction:
Improveclosure status informationVSAvoidswitch and signal system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent provides comprehensive status information through electrical switches that detect handle position and latching status, transmitting this information to the flight deck. This resolves the information loss issue by implementing feedback without requiring complex local indication mechanisms.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces potential complex mechanical indication systems with electrical switches and signals. This substitution provides detailed status information while keeping the physical structure relatively simple, as electrical systems can convey multiple states through simple binary signals.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 latch securely maintains access doors closed during flight and provides clear indications of the door's locked or unlocked status through electrical signals, enhancing safety and operational reliability.

Implementation Method 1

the plunger assembly includes a spring to facilitate movement of the plunger from its extended position to its retracted position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

the cam is engaged with the slide plate proximate to the second end of the slide plate; when the handle is moved from its pop-up position to its open position, the drive shaft and the cam are rotated such that the cam draws the slide plate in a direction towards the second end of the base

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 3

the second end of the handle is attached pivotally to the drive shaft of the rotary arm assembly; a swivel arm having a first portion attached pivotally to the swivel arm hub of the base and a second portion attached pivotally to the first end of the slide plate

Methodology Applied
Scientific EffectHinge: Hinge

Data Source

PatentEP2773827B1Rotary-handle latch
Publication Date: 2015.08.26 ALCOA INC
  • EP2773827B1 patent drawingFigure 1~2
  • EP2773827B1 patent drawingFigure 3~4
  • EP2773827B1 patent drawingFigure 5~6

AI summary

A latch (10) includes a base (12), a drive shaft (100) and cam (102), and a handle (110) attached pivotally to the drive shaft (100). The handle (110) is moveable between a closed position, a pop-up position, and an open position. A slide plate (24) is attached slidably to the base (12) and engaged with the cam (102). A swivel arm (52) is attached pivotally to the base (12) and the slide plate (24). A bolt assembly (66) is attached to the swivel arm (52), and a plunger (32) is mounted within the base (12). In its closed position, the handle (110) engages the plunger (32) to engage a switch (36) and the bolt assembly (66) engages a structure. In the handle's (110) pop-up position, the plunger (32) moves to a retracted position and disengages the switch (36). When the handle (1 10) is moved to the open position, the drive shaft (100) and cam (102) are rotated so that the slide plate (24) slides and the swivel arm (52) pivots to swing the bolt assembly (66) away from the structure.