Non-Circular Riveted Fastener for High-Strength Steel
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Solution Overview
Problem
Existing fastening solutions fail to securely attach to form-hardened and high-strength steel components, as traditional methods like stamping nuts are impractical due to hardness, and require secure against pulling out and twisting with minimal effort.
Innovation Solution
A fastening element with a non-circular outer contour, such as a square with rounded corners, is riveted into a pre-existing hole in the component, using a die to deform the edge for secure attachment, and features a central body with a thread and integral attachment lug for positive locking against rotation and pull-out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional stamping or welding methods are used to attach nuts to sheet metal, then secure fastening is achieved, but the process becomes too complex and time-consuming for high-strength steel components
Solution Approach 1:
The patent extracts the fastening function from complex multi-step processes (stamping, welding) and consolidates it into a single riveting operation. The fastening element integrates both the attachment function and the fastening function into one component that can be installed in a single step, eliminating the need for separate stamping and welding operations.
Solution Approach 2:
The fastening element is pre-formed with a specific geometry including a head, body, and tail section that enables self-riveting. The tail section is designed to be deformed during insertion to create the fastening action automatically, so the fastening action is prepared in advance through the element's geometry rather than requiring complex external equipment.
2Strength
If form-hardening is applied to steel components to increase strength, then component strength improves, but the ability to stamp or deform nuts for secure attachment is lost
Solution Approach 1:
Instead of deforming the component to attach the fastener (which is impossible with form-hardened steel), the patent inverts the approach by having the fastening element deform itself during installation. The tail section of the fastening element is designed to be deformed by the riveting process to create the secure attachment, rather than attempting to deform the hardened component.
Solution Approach 2:
The patent changes the material parameters of the fastening element itself, using a material that is soft enough to be deformed during riveting but hard enough to provide secure fastening. This allows the fastening action to occur through deformation of the fastening element rather than the component, making it compatible with form-hardened steels.
3Ease of manufacture
If a simple circular fastening element is used, then manufacturing is easy, but secure locking against rotation and pull-out cannot be achieved
Solution Approach 1:
The patent introduces asymmetry in the tail section of the fastening element, giving it a non-circular cross-section that can be deformed during riveting to create locking features. This asymmetric deformation creates mechanical interlocking that prevents rotation and pull-out, while the overall element remains simple enough for efficient manufacturing.
Solution Approach 2:
The patent uses curved or rounded features in the tail section geometry that enable controlled deformation during the riveting process. The curved surfaces allow the material to flow and form locking features when compressed, creating secure mechanical interlocking without requiring sharp edges or complex machining.
4Ease of operation
If manual alignment methods are used for fastening elements, then positioning is achievable, but automatic assembly efficiency is reduced
Solution Approach 1:
The patent incorporates visual features (such as colored markings or contrasting surface treatments) on the fastening element that provide immediate visual feedback for correct orientation. These visual indicators enable automatic assembly systems to quickly identify and position elements without complex sensing or trial-and-error procedures, maintaining both accuracy and efficiency.
Solution Approach 2:
The fastening element incorporates geometric features that replicate or complement the hole geometry, creating a natural form-fit relationship. This copying of geometric characteristics enables automatic alignment through simple mechanical guidance features in the hole that match the element's shape, eliminating the need for complex alignment mechanisms.
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 provides secure fastening against both pulling out and twisting with minimal effort, ensuring a form-fit in the direction of rotation and easy automatic alignment, suitable for form-hardened and high-strength steel components.
Implementation Method 1
a die (12) which bends the rim (11a) outwards and thereby causes the fastener lug (4) to be riveted to the rim (11a) of the hole (10)
Data Source
Figure 1~4
Figure 5
AI summary
Fixing element comprises a planar annular bearing surface (5), a fixing attachment (4) protruding over the bearing surface, an outwardly deformed edge formed on the fixing attachment by a riveting process and an aligning unit for aligning the fixing element in relation to an opening (10). Preferred Features: The fixing attachment has an outer contour which deviates from a circular shape. The aligning unit is formed by the outer contour of the bearing surface.