Sheet Metal Fastening Element Deformation Mechanism
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Solution Overview
Problem
Existing methods for attaching fastening elements to high-strength or thick sheet metal components are limited, as traditional screwing is not feasible due to thickness constraints, and stamped nuts are complex and only suitable for weaker sheet metals.
Innovation Solution
A fastening element with a flange and shoulder design, featuring a radially extending ribbed annular contact surface, where the flange presses into the sheet metal and a projection is peeled to deform and secure the element, allowing for axial and circumferential fixation, and optionally incorporating a threaded bore or peg for additional fastening means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional screwing is used to attach fastening elements to sheet metal components, then the attachment process is simple, but it is not feasible due to thickness constraints of the sheet metal
Solution Approach 1:
The patent replaces the traditional screw-threading mechanical system with a deformation-based fastening system. Instead of cutting threads into the sheet metal, the fastening element uses a projection that is deformed plastically to create an interference fit within a hole in the sheet metal, achieving secure attachment without thread cutting
Solution Approach 2:
The patent changes the physical state and dimensions of the projection through plastic deformation. The projection is inserted in a undeformed state, then subjected to radial compression forces that permanently alter its shape and dimensions, causing it to expand and lock against the hole walls, transforming it from a removable component to a permanently fixed fastener
2Reliability
If stamped nuts are used to attach fastening elements to sheet metal components, then attachment is possible, but the sheet metal is severely deformed and the process is complex
Solution Approach 1:
The patent inverts the traditional stamped nut approach. Instead of deforming the sheet metal to secure the fastener (as in stamped nuts), the fastening element itself is deformed to secure it. The projection is the component that undergoes plastic deformation, not the sheet metal, fundamentally reversing which element is modified
Solution Approach 2:
The patent separates the fastening function into distinct components: the flange for bearing surface contact, the projection for insertion and deformation, and the body for housing the fastening means. This segmentation allows each component to be optimized for its specific function and simplifies the overall attachment process
3Reliability
If stamped nuts are used to attach fastening elements to sheet metal components, then attachment is achieved, but only weak sheet metals can be processed
Solution Approach 1:
The patent changes the approach from deforming the sheet metal (stamped nuts) to deforming the fastening element's projection. This parameter change in which component undergoes deformation allows the process to work with high-strength and thick sheet metals that would be damaged by traditional stamping methods
Solution Approach 2:
The patent applies local quality by concentrating the deformation in the projection of the fastening element rather than distributing it across the sheet metal. The projection is specifically designed with material properties and geometry that enable controlled plastic deformation, while the sheet metal remains unaffected and retains its original strength and integrity
4Reliability
If the projection is deformed to fix the fastening element to the sheet metal, then secure attachment is achieved, but the sheet metal thickness and strength requirements increase
Solution Approach 1:
The patent applies partial action by deforming only the projection rather than the entire fastening element or the sheet metal. This localized deformation requires less overall material thickness while achieving sufficient attachment security through the interference fit created in the hole region
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
Enables secure attachment to high-strength sheet metals without deformation, providing a detachable and versatile fastening solution that can accommodate various shapes and sizes, including non-circular forms, and supports the use of different fastening means like threaded bores or pegs.
Implementation Method 1
From the other side, this shoulder is deformed so that it rests on the side of the metal sheet that faces away from the bearing surface of the flange
Data Source
Figure 1~3
Figure 4~7
Figure 8~11
AI summary
To attach a fastener, for example a nut having an internal thread (8), to a sheet metal component (12), it is proposed to make a hole in the sheet metal component (12) and insert the fastener into the hole until it abuts one side (13) of the sheet metal component (12) with an annular contact surface (2) formed on a flange (1). From the other side, the edge of the part of the fastener that has been inserted through the hole is sheared off, and this sheared-off part is pressed against the top of the sheet metal component. This rivets the fastener to the sheet metal component.