Self-indexing Nut Plate Spanner Bar Attachment
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Solution Overview
Problem
The existing methods for attaching wire support hardware to spanner bars in commercial aircraft require a high number of fastening operations, leading to increased part count and installation time, which is inefficient and time-consuming.
Innovation Solution
A self-indexing nut plate that engages a spanner bar without the use of mounting hardware, utilizing locator protrusions and a locking member to constrain motion, allowing for secure attachment of wire support hardware without the need for additional fasteners like nuts and washers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fastening methods (nuts and washers) are used to attach wire support hardware to spanner bars, then secure attachment is achieved, but part count and installation time increase
Solution Approach 1:
The patent combines the nut and washer into a single integrated nut plate component that attaches directly to the spanner bar. The nut plate includes a mounting surface that contacts the spanner bar and an internally threaded bore for receiving the wire support hardware, eliminating the need for separate nuts and washers while maintaining secure attachment.
Solution Approach 2:
The nut plate is pre-installed on the spanner bar before the wire support hardware is attached. The locator protrusions are already positioned on the nut plate to engage with the mounting holes, so when the wire support hardware is installed, the alignment is already prepared, reducing installation time.
2Reliability
If conventional fastening methods (nuts and washers) are used to attach wire support hardware to spanner bars, then secure attachment is achieved, but part count increases
Solution Approach 1:
The patent combines the nut and washer into a single integrated nut plate component that attaches directly to the spanner bar. The nut plate includes a mounting surface that contacts the spanner bar and an internally threaded bore for receiving the wire support hardware, eliminating the need for separate nuts and washers while maintaining secure attachment.
3Manufacturing precision
If locator protrusions engage mounting holes to constrain motion, then precise positioning is achieved, but complexity of the nut plate increases
Solution Approach 1:
The nut plate is divided into functional segments: a body portion for mounting, locator protrusions for positioning, and an internally threaded bore for fastening. This segmentation allows each feature to perform its specific function independently, achieving precise positioning without excessive overall complexity.
Solution Approach 2:
The locator protrusions automatically engage with the mounting holes in the spanner bar to self-align and constrain the nut plate position. This self-aligning mechanism eliminates the need for additional alignment features or complex positioning systems, achieving precise positioning with minimal added complexity.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An aircraft comprises a secondary support structure, and a nut plate engaging the secondary support structure. The nut plate includes at least one locator protrusion engaging a mounting hole in the secondary support structure to constrain motion of the nut plate along the secondary support structure. The nut plate further includes means for additionally constraining motion of the nut plate away from the secondary support structure.