Rotary Clinch Fastener Tooling for Low-Marking Panel Installation
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Solution Overview
Problem
Existing rotary installation methods for clinch fasteners in sheet or panel workpieces face challenges such as varying metal shapes, metal shearing, and torsional stresses, which can result in cosmetic marks and increased manufacturing complexity.
Innovation Solution
The development of new tooling for rotary presses that utilizes multiple types of reduced area displacers, including rolling ball bearings and wobbling ring displacers, to distribute force evenly and reduce friction, thereby minimizing axial and torsional stresses during the installation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If standard rotary installation displacers are used, then installation force is reduced, but cosmetic marks may still appear on the panel and manufacturing complexity increases when multiple displacer shapes are needed
Solution Approach 1:
The displacer is divided into multiple segments or lobes (typically 3-6) around the central axis, with each segment capable of independent rotation. This segmentation allows different portions of the displacer to contact and deform the panel at different locations and orientations, distributing the installation force more evenly and reducing concentrated stress that causes cosmetic marks.
Solution Approach 2:
The displacer segments are designed to rotate dynamically during the installation process, transitioning from a stationary configuration to a rotating state. This dynamic rotation enables the displacer to adapt its contact points with the panel, distributing deformation across multiple locations and reducing the likelihood of cosmetic marks while maintaining effective installation force.
2Manufacturing precision
If multiple different displacer shapes are used to better fill the volume around the fastener, then installation quality improves, but device complexity increases
Solution Approach 1:
A single multi-lobe displacer structure performs multiple functions that would otherwise require several different displacers. By configuring 3-6 lobes with varying profiles around the central axis, one displacer can create complex three-dimensional metal flow patterns, fill irregular volumes around fasteners, and adapt to different installation scenarios, eliminating the need for multiple specialized displacer tools.
Solution Approach 2:
Multiple displacer functions and geometries are merged into a single integrated multi-lobe displacer structure. The various lobes are combined around a central rotation axis, creating one unified component that can perform the work of multiple separate displacers, thereby reducing device complexity while maintaining or improving manufacturing precision.
3Power
If solid displacers are used in rotary installation, then installation torque is generated, but torsional stresses are created that can cause cosmetic marks
Solution Approach 1:
Different lobes of the displacer are designed with locally optimized qualities and profiles suited to specific tasks. Each lobe can have different geometry, material properties, or surface characteristics tailored to its specific contact zone, allowing the displacer to generate necessary torque while distributing stress locally to minimize cosmetic marks.
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 effectively reduces installation forces and torsional stresses, preventing cosmetic marks and simplifying manufacturing by allowing for different displacer shapes to be used on the same tool, thus improving the efficiency and quality of clinch fastener installation.
Implementation Method 1
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
Implementation Method 2
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 3
Fixed-position displacers evenly spaced about the tool bore are pressed a set distance and rotated in increments. This type utilizes axial oscillation to relieve panel stress following each tool stroke
Data Source
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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 rotatable such as caged ball bearings; and 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.