Aircraft Selector Lever Detent Pin Failure Detection

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Solution Overview

Problem

Conventional aircraft selector levers lack an effective mechanism to detect the failure of detent pins, which hinders maintenance efficiency and aircraft safety.

Innovation Solution

A selector lever design with a shaft, slide, and detent plates featuring obstructing features in channels, allowing for visual and tactile detection of detent pin integrity without disassembly, enabling operators to assess pin failure during normal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional selector lever design is used with detent plates and pins, then the mechanism provides redundancy allowing operation after one pin failure, but the inability to detect pin failure compromises aircraft safety and increases maintenance costs

Engineering Contradiction:
Improveaircraft safetyVSAvoiddetent pin failure detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

A sensor is introduced as an intermediary element between the detent pin and the control system. The sensor detects the position of the detent pin and generates an electrical signal to indicate whether the pin is properly engaged or has failed, enabling reliable failure detection without compromising the mechanical redundancy of the selector lever mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of repair

If conventional selector lever design is used, then the structure is simple and cost-effective, but the lack of failure detection capability requires disassembly for inspection, increasing maintenance time and costs

Engineering Contradiction:
Improvemaintenance efficiencyVSAvoidpin integrity information
Core Design Contradiction:
Ease of repairVSLoss of information

Solution Approach 1:

The sensor provides real-time feedback about the detent pin status to the control system. This feedback mechanism allows the system to know the integrity status of the detent pin without requiring physical inspection or disassembly, enabling maintenance personnel to quickly assess whether the selector lever is functioning properly and whether maintenance is needed.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3000725B1Selector lever with failure detection features
Publication Date: 2017.05.17 HAMILTON SUNDSTRAND CORP
  • EP3000725B1 patent drawingFigure 1
  • EP3000725B1 patent drawingFigure 2
  • EP3000725B1 patent drawingFigure 3A

AI summary

A selector lever (5) with redundant detent pins (13,16) and detent plates (11,14) and a method for using the selector lever (5) to test for a failure of one or more detent pins (13,16). The detent plates (11,14) include a plurality of slots (12,15) connected by a channel (17) that corresponds to a disengaged position, enabling the detent pin (13,16) to be moved from one slot (12,15) to another. The selector lever (5) includes one or more obstructing features (18,19) in the channels (17) of the detent plates (11,14). The selector lever (5) further includes indicators (20,21,22) for comparing the location of the shaft (6) with the location of the obstructing features (18,19) while the slide (10) is in the disengaged position.