Sheet-Metal Fastener Head Serrations for Higher Torque Resistance
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Solution Overview
Problem
Existing sheet-metal fasteners lack effective engagement and torque distribution, leading to reduced joint effectiveness and material pull beyond the reference plane, which limits their performance in securely fastening metal components.
Innovation Solution
A sheet-metal fastener design featuring a serrated region with knurls on the outer perimeter of the head, which increases torque required for thread engagement and material pull, and includes a self-tapping tip for easy piercing, along with a cold-forming process for manufacturing, enhancing material interaction and joint stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional smooth-headed sheet-metal fastener is used, then the fastening process is simple, but the torque distribution is ineffective and material pull occurs beyond the reference plane
Solution Approach 1:
The head features a serrated region with knurls at the outer perimeter that creates localized material engagement and torque distribution. This localized structural variation improves torque resistance and prevents material pull without requiring complex overall head design
Solution Approach 2:
The self-tapping tip performs preliminary action by piercing the material before threading engagement occurs. This preliminary piercing action facilitates easier installation and ensures proper alignment before the threaded portion engages the material
2Strength
If existing sheet-metal fasteners are used, then installation is straightforward, but thread engagement is insufficient leading to reduced joint strength
Solution Approach 1:
The shank is segmented into distinct functional zones: a self-tapping tip for initial piercing and a threaded portion for engagement. This segmentation allows each zone to perform its specific function optimally, improving both installation ease and thread engagement strength
Solution Approach 2:
The fastener utilizes parameter changes in thread geometry and tip configuration to optimize both engagement strength and installation ease. The threaded portion features specific pitch and depth parameters that balance engagement strength with rotational ease during installation
3Force
If a conventional fastener head is used, then manufacturing is simple, but torque resistance is insufficient allowing material pull beyond reference plane
Solution Approach 1:
The serrated region with knurls is formed through localized cold-forming processes that create high torque resistance only where needed at the outer perimeter. This localized approach achieves superior torque resistance without requiring complex manufacturing of the entire head structure
Solution Approach 2:
The cold-forming process creates self-service features where the knurls automatically form the serrated pattern during manufacturing. The process utilizes the material's own plasticity to create the torque-resisting features without additional machining or assembly steps
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 serrated region enhances thread engagement and torque distribution, allowing for more effective material pull beyond the reference plane, resulting in a stronger and reusable joint with increased torque resistance.
Implementation Method 1
The serrated region may comprise a plurality of knurls... increases torque required for thread engagement and material pull
Implementation Method 2
along with a cold-forming process for manufacturing, enhancing material interaction and joint stability
Data Source
AI summary
Disclosed is a sheet-metal fastener configured to join two components, such as sheet-metal. The sheet-metal fastener comprising a head and a shank. The head may define an undercut region and a serrated region. The serrated region can be positioned at an outer perimeter of the head. The serrated region can be composed of a plurality of knurls. The shank extends perpendicularly from the undercut region and comprises one or more threads.