Rotary Clinch Fastener Tooling With Rolling Displacers
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Solution Overview
Problem
Existing rotary installation tools for clinch fasteners face issues such as varying metal displacement shapes, material shearing, and torsional stresses that cause cosmetic marks and increased manufacturing complexity.
Innovation Solution
The tooling employs multiple types of displacers, including fixed, rolling, incremental, and oscillating designs, which reduce axial and torsional stresses by converting installation force to torque and minimizing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If standard rotary installation displacers are used, then installation force is reduced, but cosmetic marks are caused on the opposite side of the panel
Solution Approach 1:
The displacer is segmented into multiple reduced-area contact zones instead of a single large contact surface. This segmentation allows the installation force to be distributed through multiple smaller points, reducing the overall axial compressive stress that causes cosmetic marks while maintaining effective metal displacement around the fastener
Solution Approach 2:
The displacer features localized reduced-area contact zones strategically positioned to apply force only where needed for metal displacement. This local quality approach concentrates force application to specific areas rather than distributing it across the entire panel surface, reducing unwanted cosmetic marks while achieving effective fastener installation
2Manufacturing precision
If multiple different shape displacers are used to better fill the area around the fastener, then manufacturing complexity increases
Solution Approach 1:
Instead of creating one complex displacer with multiple geometric features, the invention segments the displacer into multiple simpler reduced-area contact zones. Each zone has a simple geometry that is easy to manufacture, but collectively they achieve the desired composite fill shape around the fastener, reducing manufacturing complexity while maintaining precision
3Loss of substance
If solid displacers slide around the installation hole, then material is sheared from the panel surface, but friction increases installation force
Solution Approach 1:
The displacer incorporates rolling elements that transition from static sliding contact to dynamic rolling contact as the tool rotates during installation. This dynamic change allows the displacer to move around the installation hole with reduced friction, decreasing installation force while minimizing material shearing through controlled metal displacement
4Ease of operation
If solid displacers are used in rotary installation, then torsional stresses are created that cause cosmetic marks
Solution Approach 1:
The displacer is segmented into multiple reduced-area contact zones arranged symmetrically around the fastener. This segmentation allows the rotary installation tool to apply force through multiple points that balance each other, reducing net torsional stress on the panel while maintaining effective metal displacement and preventing cosmetic marks from torsional loading
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 effectively reduces installation forces, minimizes material loss, and eliminates torsional stresses, ensuring a smooth and stress-free installation process without cosmetic damage.
Implementation Method 1
rotary installation utilizes a reduced area displacers to reduce the axial installation force by converting much of the installation force to installation torque
Implementation Method 2
Multiple displacers where the displacers roll on the surface of the metal while being pushed axially, such as ball bearings. The result is reduced friction given that the displacers are not dragging around the surface of the installation hole but are rolling instead
Data Source
AI summary
Tooling is held within the nose of a rotary punch and as the tool is rotated and forced against a workpiece a fastener within the tool becomes affixed to the workpiece. The tools have displacers which non-destructively deform and reshape the workpiece without any loss of workpiece material. The tools have various types of displacers including: tapered and arcuate displacers which act in concert to progressively act upon the workpiece; spherical displacers which may be fixed. or a full-circle displacer ring which wobbles as it presses against the workpiece. In the case of fixed spherical displacers, a multi-stroke method can be employed where the tool is rotated after each stroke in a group of installation strokes.