Rivetless Nut Plate with Noncircular Cross-Section
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Solution Overview
Problem
In manufacturing, connecting structures with fastener systems, especially in composite materials, is challenging due to difficulties in achieving sufficient interference to resist rotation without causing inconsistencies, and the use of rivets or gang channels can increase weight, time, and costs.
Innovation Solution
A fastener system comprising a nut plate with a body having a circular channel and a noncircular outer surface, and a flange to hold a nut element, which reduces the need for rivets and gang channels by using an interference fit to prevent rotation, thereby minimizing inconsistencies and installation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rivets or gang channels are used to prevent nut plate rotation, then rotation resistance is improved, but weight increases
Solution Approach 1:
The nut plate body features a noncircular outer surface cross-section that corresponds to a noncircular hole in the composite structure. This asymmetric geometry creates an interference fit that prevents rotation of the nut plate within the hole, eliminating the need for additional rivets or gang channels while maintaining rotation resistance.
2Reliability
If interference is increased to prevent rotation in composite materials, then rotation resistance is improved, but inconsistencies in composite material increase
Solution Approach 1:
The noncircular outer surface of the nut plate body creates a geometric interference fit within a noncircular hole, providing rotation resistance through shape compatibility rather than excessive interference. This approach prevents rotation while maintaining consistency in the composite material by avoiding the need for high-interference circular fits.
3Reliability
If traditional nut plates with rivets are used, then rotation resistance is improved, but device complexity increases
Solution Approach 1:
The nut plate design integrates the rotation prevention function directly into the body through a noncircular outer surface cross-section. This merges the rotation resistance mechanism with the nut plate structure itself, eliminating the need for separate rivets or gang channels and thereby reducing fastener system complexity.
Solution Approach 2:
The design extracts and eliminates the need for separate rotation prevention components (rivets, gang channels) by incorporating the rotation resistance function directly into the nut plate body through its noncircular geometry. This simplifies the overall fastener system by removing unnecessary elements.
4Reliability
If rivets and gang channels are used for installation, then rotation resistance is improved, but installation time increases
Solution Approach 1:
The nut plate body's noncircular outer surface integrates the rotation prevention function into the main component, merging multiple functions (fastening and rotation resistance) into a single element. This eliminates the need for separate installation steps involving rivets or gang channels, thereby reducing installation time.
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
This solution allows for efficient and cost-effective connection of structures with reduced inconsistencies and weight, enabling easier installation and maintenance, particularly in composite materials, by using a nut plate with a noncircular cross-section for enhanced resistance to rotation.
Implementation Method 1
Rivetless nut plates rely on friction to resist rotation in the hole
Data Source
AI summary
A method and apparatus for fastening structures. A first end of a body is placed into a hole on a first side of the structures. The body has an outer surface with a noncircular cross-section. A nut element is positioned on a flange at a second end of the body. A bolt is moved into a channel at the first end of the body towards the nut element on the flange on the second end of the body on the first side the structures. The bolt and the nut element are fastened to each other.