Counterbored Rivet Nut Sleeve for Thread Alignment and Seating Check
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Solution Overview
Problem
Existing rivet nut systems lack an effective alignment apparatus between the internal threads of the rivet nut and the external threading of the installation tool or fastener, leading to issues like cross-threading and improper installation, especially during over-upset conditions.
Innovation Solution
A rivet nut with a counterbore cavity and a cylindrical bushing sleeve that snugly fits within the counterbore cavity, providing alignment and guiding the external threading of the installation tool or fastener into optimal rotational mating with the internal threads of the rivet nut, enhancing control during upset formation and preventing cross-threading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If no alignment apparatus is provided in the rivet nut, then the device complexity is reduced, but cross-threading and improper installation occur leading to poor manufacturing precision
Solution Approach 1:
A bushing sleeve is introduced as an intermediary component between the installation tool mandrel and the rivet nut internal threads. The bushing sleeve has an inner diameter that guides the mandrel and an outer diameter that fits within the counterbore cavity, providing precise alignment without requiring complex internal threading modifications to the rivet nut itself.
Solution Approach 2:
The alignment function is separated from the rivet nut body by using a distinct bushing sleeve component. This segmentation allows the bushing to be optimized specifically for alignment purposes while the rivet nut maintains its primary fastening function, reducing overall system complexity.
2Reliability
If the counterbore cavity has parallel sides, then the manufacturing process is simpler, but control during upset formation is insufficient leading to poor installation reliability
Solution Approach 1:
The counterbore cavity is designed with different geometries in different regions: the upper portion has parallel sides for ease of manufacture and bushing insertion, while the lower portion has converging sides that provide mechanical control during upset formation. This local differentiation of geometry optimizes both manufacturing and installation reliability.
3Reliability
If no bushing sleeve is used, then the device complexity is lower, but visual confirmation of proper seating cannot be provided leading to poor installation reliability
Solution Approach 1:
The bushing sleeve serves as a visual indicator component. When properly installed, the bushing's position and appearance provide immediate visual confirmation that the rivet nut is correctly seated and aligned, allowing operators to verify installation quality without additional tools or procedures.
Data Source
AI summary
An apparatus providing mating alignment between internal threading of a rivet nut and the external threading of the mandrel of an unclaimed installation tool before anchoring the rivet nut in a hole in a substrate, or the external threading of an unclaimed threaded fastener after anchoring in the substrate hole. The improvements include a bushing sleeve seated in a counterbore in the rivet nut, for guiding the external threading of the mandrel or fastener to the internal threading of the rivet nut. The sleeve also enables play during upset of the rivet nut, and provides visual confirmation whether the rivet nut has been properly anchored in the hole of substrate.