Compression Fitting Integral Anti-Rotation Key Prevents Sensor Lead Damage
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Solution Overview
Problem
Existing sensor fittings for gas turbine engines often omit or lose anti-rotation pins, leading to damage or severing of sensor leads due to follower rotation, and potential ingestion into the engine, causing damage to critical components.
Innovation Solution
A compression fitting design with an integral anti-rotation key on the follower that is constrained within a keyway in the housing, preventing follower rotation during seal compression, eliminating the need for separate anti-rotation pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate anti-rotation pin is used to prevent follower rotation, then sensor leads are protected from damage, but the device complexity increases and assembly errors occur when pins are omitted
Solution Approach 1:
The anti-rotation key is merged with the follower as an integral feature rather than being a separate pin component. The key is formed directly from the follower material, eliminating the need for separate anti-rotation pins and reducing assembly complexity while maintaining protection of sensor leads from rotation damage
Solution Approach 2:
The follower serves multiple functions: it compresses the seal against the housing, prevents rotation through the integral anti-rotation key, and protects sensor leads. This multi-functionality eliminates the need for separate anti-rotation pins and reduces the overall number of components required in the fitting assembly
2Reliability
If a separate anti-rotation pin is used, then follower rotation is prevented, but the risk of pin separation and engine ingestion increases
Solution Approach 1:
By integrating the anti-rotation key into the follower as a single monolithic component, the invention eliminates the risk of pin separation and engine ingestion. The key cannot detach from the follower since it is formed as one piece, removing this harmful factor while maintaining rotation prevention
Solution Approach 2:
The integral anti-rotation key is designed as a permanent feature of the follower that cannot separate or be lost. This eliminates the risk associated with separate pins that could detach and be ingested by the engine, as the key remains permanently attached to the follower throughout its service life
3Reliability
If the follower is made axially movable to compress the seal, then sealing is achieved, but the follower may rotate and damage sensor leads
Solution Approach 1:
The anti-rotation key features an asymmetric rectangular cross-section that fits into a corresponding keyway in the housing. This asymmetric geometry prevents rotational movement of the follower while allowing axial movement for seal compression, thereby achieving sealing without rotation damage to sensor leads
Solution Approach 2:
The keyway in the housing is segmented into discrete engagement points that interact with the anti-rotation key. This segmentation allows the follower to move axially while the keyway structure prevents rotational movement, separating the axial compression function from the rotational constraint function
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
Prevents damage to sensor leads by ensuring the follower does not rotate during seal compression, reducing the risk of lead damage and engine ingestion of anti-rotation components.
Implementation Method 1
a compressible seal seated at one end of the axial cavity, the seal being compressible against the cavity sidewall and signal transmitting leads
Implementation Method 2
The follower's anti-rotation key is rotatably constrained within the keyway thereby preventing rotation of the follower as the driving member translates the follower along the axial passage
Data Source
AI summary
A compression fitting includes a housing, a compressible seal, a follower and a driving member. The housing includes an axial cavity having a lateral sidewall that includes an axial keyway therein. The cavity terminates at a first end portion thereof at a seat. The compressible seal may receive a signal transmitting lead therethrough, and is disposed within the cavity and seated on the seat. The follower is axially movable within the cavity for selective engagement with the seal for axially compressing the seal against the seat, the sidewall of the cavity and the signal transmitting lead. The follower includes an integral key that extends laterally outward therefrom and is received within the keyway, and an axial bore for accommodation therewithin of the lead. The driving member is rotatably mounted on the housing and engageable with the follower such that rotation of the driving member causes an axial translation thereof.