Positive Locking Keeper for Aircraft Panel Latch
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Solution Overview
Problem
Aircraft panel latch assemblies require a secure and adjustable locking keeper that maintains its adjustment when engaged, while preventing rotational movement to withstand vibrations and rattling during travel.
Innovation Solution
A positive locking keeper with a keeper housing, coupling, nut, and wave spring that allows for adjustable engagement with a latch assembly, utilizing a detent pin and indentations to prevent rotational movement when loaded, and a spring to bias the nut away from the housing when unloaded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the keeper is made adjustable to accommodate different panel positions, then adaptability is improved, but the risk of losing adjustment due to vibration and rattling increases
Solution Approach 1:
The keeper employs a dynamic locking mechanism where the detent pin can move between engaged and disengaged states. When the nut is rotated to adjust the panel position, the detent pin disengages from the indentation, allowing rotation. Once adjusted, the detent pin engages with the indentation to lock the nut in place, preventing further rotation and maintaining the adjustment despite vibrations and rattling during travel.
Solution Approach 2:
The detent pin acts as an intermediary element between the nut and the keeper housing. It transfers the locking function from the nut to the housing by engaging with the indentation on the nut's peripheral edge. This intermediary mechanism ensures that the adjustment is securely maintained without requiring the nut itself to be permanently fixed.
2Ease of operation
If the nut is freely rotatable for adjustment, then ease of operation is improved, but rotational movement occurs under load causing loss of adjustment
Solution Approach 1:
The system dynamically transitions between two states: during adjustment, the detent pin is disengaged allowing the nut to rotate freely for easy operation; during operation under load, the detent pin engages with the indentation to prevent rotational movement and maintain positional stability. This dynamic state change resolves the contradiction between ease of adjustment and operational stability.
Solution Approach 2:
The wave spring applies a preliminary biasing force to keep the detent pin disengaged from the indentation during normal operation, preventing rotational movement before vibrations or rattling can cause loosening. When adjustment is needed, the nut rotates against this biasing force, and the detent pin naturally engages to lock the position, counteracting any subsequent loosening tendencies.
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 secure engagement and adjustment of the latch assembly while preventing rotational movement under load, maintaining stability and preventing loss of adjustment during operation.
Implementation Method 1
A wave spring may be positioned between the keeper housing and the nut, the wave spring serving to bias the nut away from the keeper housing
Implementation Method 2
The positive locking keeper may also include a spring disposed within the opening in the keeper housing that holds the detent pin. The spring biases the detent pin away from the keeper housing.
Data Source
AI summary
A positive locking keeper for use with an aircraft panel latch assembly having a hook for engaging the positive locking keeper includes a keeper housing having a central opening, and a coupling having a head and a shaft extending therefrom. The head engages the latch assembly and the shaft extends through the housing with the head disposed on the first side. A detent pin is disposed within an aperture of the keeper housing. The positive locking keeper also includes a nut positioned on the second side of the keeper housing. The shaft engaged the nut. The nut includes indentations on a peripheral edge to receive a portion of the detent pin. In a first position, the detent pin engages one of the indentations and prevents rotation of the nut. In a second position, the detent pin does not engage the indentations and the nut is able to rotate.