Self-Locking Plug Anti-Rotation Interference Mechanism
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Solution Overview
Problem
Existing removable self-locking plugs for turbine engine inspection apertures fail to securely prevent axial rotation of the sleeve during core installation and removal, leading to potential loosening or misalignment issues.
Innovation Solution
A self-locking plug design featuring a lock between the sleeve and core with an anti-rotation feature, including a circumferentially extending interference surface and radially biased cantilevered interference tabs, which prevent axial rotation by engaging a shelf and ridge during core removal, ensuring rotational stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional removable plug is used, then the aperture can be opened for inspection, but the sleeve rotates axially during core installation and removal causing loosening or misalignment
Solution Approach 1:
The plug is divided into distinct functional components: a sleeve that interfaces with the aperture, a core that threads through the sleeve, and a lock mechanism with interference tabs and surfaces. This segmentation allows each component to perform its specific function while working together to prevent rotation during operations.
Solution Approach 2:
The lock mechanism uses dynamic interference tabs that are radially biased against interference surfaces. During core installation and removal, these tabs flex and engage with the tapered interference surfaces to dynamically prevent axial rotation of the sleeve while still allowing the core to be installed and removed.
2Ease of operation
If the sleeve is made rotatable for ease of operation, then core installation is simplified, but the plug loses rotational stability and may loosen due to vibration
Solution Approach 1:
The interference tabs are pre-biased radially outward to contact the interference surfaces before core installation begins. This preliminary engagement creates immediate rotational stability and prevents the sleeve from rotating during the entire installation and removal process, countering the loosening effect of vibration.
Solution Approach 2:
The interference surfaces are tapered at specific angles to convert axial forces during core installation and removal into radial forces that press the interference tabs against the surfaces. This parameter change ensures that the plug remains securely locked against rotation while allowing smooth core operations.
3Stability of the object's composition
If a lock mechanism with interference tabs is added, then rotational stability is improved, but the device complexity increases
Solution Approach 1:
The lock mechanism combines multiple functions into a single integrated structure: the interference tabs serve both as rotational locks and as guides for core alignment, while the tapered interference surfaces provide both the locking action and the wear interface. This merging reduces the number of separate components needed.
Solution Approach 2:
The interference tabs are spring-biased to automatically engage with the interference surfaces when the core is inserted, and automatically disengage when the core is removed. The mechanism serves itself by using the core installation and removal actions to drive the locking and unlocking cycles without requiring separate actuation mechanisms.
Data Source
AI summary
A self-locking plug is provided that includes a lock carried between a sleeve and a core. The sleeve has an anti-rotation feature for reducing axial rotation of the sleeve during at least one of core removal and core installation. The core extends through the sleeve. The lock includes a first component and a second component. The first component has a protrusion that extends radially out to a circumferentially extending interference surface. The second component has an interference tab that is radially biased against the interference surface.