Compact Locking Device for Borescope Plugs
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Solution Overview
Problem
Existing locking devices for borescope plugs in aircraft engines are not highly reusable, prone to damage, have sharp edges, require special tools or knowledge, and are not compact or lightweight, making them difficult to manufacture and maintain.
Innovation Solution
A compact locking device comprising a carrier with apertures, ball bearings or roller elements, a body with detents and ridges, and a band spring that allows for elastic deformation upon rotation, providing a secure and reusable locking mechanism without sharp edges or loose parts, and requiring no special tools or knowledge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional locking features (safety wire, tab washers, cotter clips) are used, then the borescope plug can be locked, but the device becomes complex, requires special tools for installation and removal, and is prone to damage
Solution Approach 1:
The locking mechanism is segmented into discrete components: a body with multiple detents, roller elements that engage with the detents, and a carrier with apertures. This segmentation allows each component to perform a specific function while maintaining overall simplicity and reliability of the locking system.
Solution Approach 2:
The locking mechanism is designed to be self-contained and self-operating. The roller elements automatically engage with the detents when the body is rotated, and the spring provides continuous engagement force without requiring external tools or additional locking components. The system serves itself by using the rotational motion of installation/removal to automatically lock or unlock.
2Reliability
If multiple locking components are used to prevent loosening, then reliability improves, but the device becomes heavier and more difficult to manufacture
Solution Approach 1:
Multiple locking functions are merged into a single integrated mechanism. The body with detents, the roller elements, and the spring work together as one unified locking system rather than separate locking components. This merging reduces the number of parts to manufacture while maintaining reliable anti-loosening functionality through the combined action of the detent-roller-spring assembly.
Solution Approach 2:
The manufacturing simplicity is achieved by using standard, off-the-shelf components such as ball bearings or roller elements and conventional springs. By selecting common components with standard parameters and materials, the invention avoids complex manufacturing processes while ensuring reliable locking performance through proper parameter selection of the detent geometry and spring characteristics.
3Reliability
If conventional locking mechanisms are used, then the plug can be secured, but sharp edges and loose parts create safety hazards and wear
Solution Approach 1:
The use of roller elements (ball bearings or cylindrical rollers) with curved surfaces replaces sharp-edged locking components. The rounded geometry of the rollers eliminates sharp edges that could cause injury or damage, while the rolling contact reduces wear compared to sliding friction. The curved surfaces naturally guide the locking action and distribute contact forces evenly.
4Reliability
If a locking mechanism is designed to be robust and reusable, then reliability improves, but the device size and weight increase
Solution Approach 1:
The locking mechanism is designed for unlimited reuse without maintenance or tooling. The self-contained design with automatic engagement and disengagement allows the same mechanism to be used repeatedly for installing and removing borescope plugs. The robustness for reusability is achieved through the simple, tool-free operation that avoids wear from repeated tool insertion and removal, keeping the weight minimal while ensuring long-term reliability.
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 device provides a robust, reusable locking solution that prevents borescope plugs from loosening due to mechanical vibrations, thermal cycling, and pressure pulsations, while maintaining ease of use and manufacturing simplicity, with adjustable torque levels and reduced wear on components.
Implementation Method 1
the plurality of roller elements travel across the band spring to cause elastic deformation of the band spring when the body is rotated in a first direction about a central axis of the body
Implementation Method 2
a plurality of roller elements, each roller element partially disposed in a corresponding slot
Data Source
AI summary
A compact, highly-reusable, locking device includes a carrier, roller elements, a body, and a band spring. The carrier includes a plurality of apertures for receiving each a corresponding roller element. The body includes a plurality of detents separated by ridges. The number of detents is different than the number of roller elements. The body is at least partially received in the carrier such that the detents are in radial alignment with the apertures. The band spring is disposed about the roller elements. The roller elements travel across the detents and ridges to cause elastic deformation of the band spring when the body is rotated about a central axis.