Aircraft Door Handle Lock Assembly with Automatic Cam Mechanism

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Solution Overview

Problem

Current aircraft door handle lock assemblies fail to ensure the door is latched or locked when the outside handle is in a flush position, lack a positive lock to prevent accidental opening, and are complex and difficult to operate.

Innovation Solution

A door handle lock assembly with a housing, an interconnecting member that can be axially moved and rotated, and a locking mechanism that engages and disengages to secure the door, featuring a spring bias and handles on both sides to facilitate locking and unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the outside handle is positioned flush with the outer surface to reduce drag, then aerodynamic performance is improved, but the door cannot be ensured to be latched or locked

Engineering Contradiction:
ImprovedragVSAvoiddoor locking reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The locking mechanism is segmented into distinct functional components: an interconnecting member for handle movement, a lock member for engagement/disengagement, and a cam mechanism for automatic locking. This segmentation allows the flush handle position to be maintained while the locking function operates independently through the cam mechanism's automatic engagement when the handle is in the flush position.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a complex mechanism is used to ensure positive locking, then door security is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvepositive lockingVSAvoidoperation simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking and unlocking functions are merged into a single continuous motion of the handle. The interconnecting member connects both handles and the lock member, so that moving either handle automatically actuates the cam mechanism to engage or disengage the locking pins, eliminating the need for separate locking and unlocking operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cam mechanism is designed to automatically engage the locking pins with the locking surfaces when the handle is moved to the flush position, and automatically disengage when the handle is moved to the operating position. This self-actuating mechanism eliminates the need for additional controls or complex manual operations to ensure positive locking.

Inventive Principle:
Principle #25Self-service

3Reliability

If separate locking mechanisms are added to prevent accidental opening, then door security is improved, but device complexity increases

Engineering Contradiction:
Improveaccidental opening preventionVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The handle mechanism serves multiple functions: it controls the aerodynamic position of the outside handle, actuates the locking pins through the cam mechanism, and provides the operating interface for both interior and exterior access. This multi-functionality eliminates the need for separate locking mechanisms while ensuring positive locking and preventing accidental opening.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 ensures the door is securely locked and can only be unlocked by intentional operation from either side, simplifying the operation while maintaining a flush exterior handle to reduce drag.

Implementation Method 1

A spring bias and handles on both sides to facilitate locking and unlocking

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP1999324B1Door handle lock assembly with automatic lock and retract
Publication Date: 2014.03.26 BELL HELICOPTER TEXTRON INC
  • EP1999324B1 patent drawingFigure 1
  • EP1999324B1 patent drawingFigure 2
  • EP1999324B1 patent drawingFigure 3

AI summary

A door handle lock assembly includes a housing configured to be attached to a door. A interconnecting member is rotatably and axially movably supported by the housing. A first handle is fixed to the interconnecting member at a first end of the interconnecting member and a second handle is fixed to the interconnecting member at a second end of the interconnecting member. The door is between the second handle and the housing. The door handle lock assembly is changed from a locked condition to an unlocked condition by axially moving the interconnecting member from a first position to a second position and then rotating the interconnecting member.