Pivoting Barrel Nut Assembly for Blind Fastener Alignment
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Solution Overview
Problem
Conventional barrel nuts are limited in accommodating fastener stem angle variances outside the cross-sectional plane, leading to improper seating and excessive fatigue, and require visual access for installation, which is not feasible in all applications, especially in high-load situations like aircraft wing box mounting.
Innovation Solution
A two-part barrel nut design with a first and second part that are pivotable relative to each other and the structure, allowing for self-alignment and load transmission across a larger area, enabling blind installation and accommodating deviations in fastener stem angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional single-part barrel nut is used, then the structure is simple and manufacturing is easy, but it cannot accommodate fastener stem angle variances outside the cross-sectional plane, leading to improper seating and excessive fatigue
Solution Approach 1:
The barrel nut is divided into two separate parts: a first part that contacts the structure and a second part that engages with the fastener stem. This segmentation allows each part to perform its specific function independently, enabling the assembly to accommodate fastener angle variances while maintaining structural integrity and load transmission capability.
2Reliability
If a conventional barrel nut requires visual access for installation, then seating can be checked to ensure proper installation, but this places significant limitations on applications where visual access is difficult or impossible
Solution Approach 1:
The two-part barrel nut assembly performs self-alignment through its pivoting mechanism, automatically ensuring proper seating without requiring visual inspection. The first part pivots relative to the second part to accommodate angle variances and self-align with the structure bore, providing reliable installation in blind conditions where visual access is impossible.
3Ease of operation
If a conventional barrel nut is used in blind installation, then installation is simplified, but the fastener stem angle variances cause the barrel nut to seat incorrectly, resulting in loads being transmitted across a much smaller region
Solution Approach 1:
The barrel nut assembly incorporates dynamic pivoting capability between the first and second parts. The first part can pivot relative to the second part about at least one axis, allowing the assembly to adapt to fastener angle variances during blind installation while maintaining proper load transmission across the intended contact area, preventing incorrect seating and associated reliability issues.
Data Source
AI summary
A barrel nut for a fastener is disclosed. The barrel nut is configured to prevent axial movement of the fastener relative to a structure on which the fastener is installed. The barrel nut comprises a first part and a second part pivotable relative to the first part.