Aerospace Fitting With Internal Locking Pockets
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Solution Overview
Problem
Existing tube fittings in aerospace applications require external lockwire for secure engagement, which is costly, prone to breakage, and increases space requirements, while also posing hazards due to exposed lockwire.
Innovation Solution
A fitting design featuring a tubular portion with circumferentially spaced pockets to engage an internal locking mechanism of a nut, eliminating the need for lockwire by providing anti-rotation force through these pockets, ensuring secure connection without external locking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lockwire is used to secure the nut to the fitting, then the connection reliability is improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent removes the external lockwire component entirely and replaces it with an internal locking mechanism integrated into the nut. The locking balls are contained within the nut structure, eliminating the need for separate lockwire that extends outside the assembly. This extraction of the locking function from an external component to an internal mechanism resolves the contradiction by maintaining reliability while reducing device complexity.
Solution Approach 2:
The locking balls are nested within the nut structure, with the nut containing the locking balls that engage with pockets in the fitting. This nested arrangement integrates the locking mechanism within the existing components rather than adding external elements, thereby maintaining connection reliability while reducing overall device complexity and space requirements.
2Reliability
If lockwire is used to prevent unintentional loosening, then the anti-rotation capability is improved, but the risk of breakage and hazards increases
Solution Approach 1:
The patent extracts the locking function from the vulnerable external lockwire and relocates it to internal locking balls contained within the nut. This eliminates the exposed lockwire that is prone to breakage from vibrations and wear, while maintaining the anti-rotation capability through the pocket-and-ball engagement mechanism.
Solution Approach 2:
The internal locking mechanism provides built-in protection against the hazards that affect external lockwire. The locking balls are protected within the nut structure from environmental factors, vibrations, and wear that cause external lockwire to break, thereby cushioning against the harmful effects before they can cause failure.
3Reliability
If external lockwire is used for locking, then the security of engagement is improved, but the cost and space requirements increase
Solution Approach 1:
The patent merges the locking function into the nut structure itself, combining the fastening and locking functions in a single integrated component. The nut contains the locking balls that engage with the fitting pockets, eliminating the need for separate lockwire material. This merging maintains security of engagement while reducing the total quantity of material required.
Solution Approach 2:
The nut is designed with multi-functionality, serving both as the fastening element and the locking mechanism. The same nut that secures the fitting to the tube also contains the locking balls that prevent unintentional loosening, eliminating the need for additional lockwire components and reducing overall material requirements.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A fitting (10,42,60) for use with a nut (32) with an internal locking mechanism (34) includes a first tubular portion (12,44,62) with a first end (20) and a first outer diameter for connecting to a first object; a second tubular portion (14,46,64) with a second end (22) and a second outer diameter for connecting to a second object; a transition portion (16,52,70) connecting the first tubular portion and the second tubular portion for fluid communication between the first tubular portion and the second tubular portion; and a plurality of pockets (24,48,65) spaced circumferentially around the second tubular portion to engage the internal locking mechanism (34) of the nut.