Blind Rivet Element Curvature for Controlled Bead Formation
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Solution Overview
Problem
Existing blind naval elements fail to consistently form a bead at a predetermined location during setting, limiting their use in brittle and soft materials, and they lack sufficient clamping force and rotational strength.
Innovation Solution
A blind naval element with a radially outwardly projecting setting contour, featuring a pre-shaped curvature between the adjustment contour and internal thread, allowing for controlled deformation and precise bead formation at a predetermined location, enhancing clamping force and rotational strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional blind naval element is used without pre-formed curvature, then the structure is simpler and manufacturing is easier, but the bead does not form at a predetermined location and the element cannot be used in brittle or soft materials
Solution Approach 1:
The patent applies preliminary action by pre-forming a curvature (bulge or boring) in the shaft wall at the desired bead formation location before the setting process. This pre-prepared geometric feature guides the deformation during setting, ensuring the bead forms exactly at the predetermined location. The curvature is created during manufacturing of the blind naval element itself, allowing controlled deformation without requiring complex setting tools or multiple operations.
2Strength
If the shaft wall thickness is increased to enable bead formation in thicker materials, then the element can be used in thicker materials, but the clamping force decreases due to higher seed force requirements
Solution Approach 1:
The patent applies local quality by creating a localized curvature (bulge or boring) at the specific location where bead formation is needed, rather than requiring uniform wall thickness throughout the shaft. This localized geometric feature concentrates the deformation in a specific area, allowing the blind naval element to accommodate thicker materials while maintaining high clamping force. The curvature radius and positioning are optimized to achieve the desired balance between material thickness capability and clamping force.
3Strength
If a larger outer diameter is used to increase rotational strength, then the rotational strength increases, but the element becomes more difficult to insert into smaller bores
Solution Approach 1:
The patent applies dimensionality change by utilizing the radial dimension of the shaft wall to create the curvature feature, rather than increasing the overall outer diameter of the element. The curvature is formed as a localized feature in the shaft wall thickness direction, allowing the blind naval element to maintain a compact outer diameter for easy insertion while achieving high rotational strength through the optimized curvature geometry and resulting perforated body structure.
4Measurement precision
If the setting contour is made larger to improve centering, then the centering capability improves, but the available space for curvature formation is reduced
Solution Approach 1:
The patent applies preliminary action by pre-forming the curvature at an optimized position relative to the setting contour during manufacturing. The curvature is positioned in the region between the setting contour and the internal thread, where there is sufficient space available. This pre-positioning allows the curvature to serve as an effective centering feature while maintaining adequate volume for the curvature formation, achieving both precise centering and sufficient deformation space.
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
The solution enables precise bead formation at a predetermined location, increasing clamping force and rotational strength, allowing the blind naval element to be used in thicker materials and brittle substances, while maintaining high rotation resistance and ease of disassembly.
Implementation Method 1
a radially outwardly curved bead is formed on the shaft, outside the bore between the head and the internal thread
Data Source
Figure 1
AI summary
In order to further develop a blind rivet element (5) comprising a head (51), an adjoining hollow shaft (53), the outer side of which has an outer diameter smaller than the head (51), and an internal thread (54) provided inside the shaft (53) and having an axial separation from the head (51), in such a way that when installed the blind rivet element always forms a controlled deformation, in particular in the form of a bulge, at the same specifiable location, it is proposed that the shaft (53) is provided with a radially outwardly protruding adjustment contour (55) in the region of the head (51), that the shaft (53) has a curvature (57) formed in the radial direction and that said curvature (57) is arranged between the adjustment contour (55) and the internal thread (54).