Arrowhead-Barb Fastener for Adhesive-Free Honeycomb Panels
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Solution Overview
Problem
Existing self-piercing fasteners are not suitable for honeycomb panels as they require preparation such as drilling or milling and often rely on adhesives for attachment, which limits their performance.
Innovation Solution
A self-piercing fastener with a metal baseplate featuring arrowhead-shaped barbs with compound tapers that engage the honeycomb structure for strong attachment without adhesives, allowing for one-step installation and a secondary fastener for additional attachment means like threads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional self-piercing fasteners are used on honeycomb panels, then preparation steps (drilling or milling) are required, but this increases installation time and complexity
Solution Approach 1:
The fastener performs its own installation function by piercing the honeycomb panel directly with its barbs, eliminating the need for separate drilling or milling operations. The barbs self-pierce through the panel and anchor themselves in the cells during a single pressing motion.
Solution Approach 2:
The barbs are pre-configured with compound tapers and arrowhead shapes that enable them to pierce the panel immediately upon contact, without requiring any preliminary hole preparation. The geometry is designed in advance to facilitate direct piercing and anchoring.
2Strength
If adhesives are used to attach fasteners to honeycomb panels, then attachment strength is improved, but this adds complexity and curing time to the installation process
Solution Approach 1:
The patent replaces the chemical bonding mechanism (adhesives) with a purely mechanical anchoring system. The barbs physically interlock with the honeycomb cells through piercing and bending, creating a mechanical fastener that requires no chemical compounds or curing processes.
Solution Approach 2:
The adhesive component is completely removed from the fastening system. The attachment mechanism relies solely on the mechanical interlocking of the barbs with the panel structure, eliminating the need for any adhesive substances or associated application procedures.
3Reliability
If multiple application steps are used for fastener installation, then attachment reliability is improved, but this increases installation time and reduces productivity
Solution Approach 1:
The piercing and anchoring functions are merged into a single simultaneous action. As the barbs pierce the panel during the pressing motion, they automatically bend and anchor themselves in the cells, achieving both penetration and secure attachment in one continuous motion without separate steps.
Solution Approach 2:
The installation process maintains continuous useful action throughout the pressing motion. The barbs continuously pierce and anchor the panel from the moment of contact until the fastener is fully installed, with no idle periods or separate operations required to achieve attachment.
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 fastener provides a strong, adhesive-free attachment to honeycomb panels by deflecting and biting into the internal columns, ensuring secure engagement and allowing for additional components to be affixed through the base plate.
Implementation Method 1
the barbs engage the vertically-spaced, internal columns of the honeycomb structure, which causes the barbs to deflect in random directions. As a result, the surfaces of the barbs, including the back edges, engage and bite into the honeycomb columns.
Data Source
Figure 1~2
Figure 3~5
Figure 6~7A
AI summary
A self-piercing fastener having a planar base plate with a top, a bottom, and a peripheral edge. A plurality of prongs are fixed to the peripheral edge and extend downward past the bottom of the baseplate. Each of the prongs has a central axis and an arrowhead-shaped barb fixed to a distal end. Each barb has opposed front edges extending from the tip, and opposed back edges oriented at a reverse acute angle relative to the central axis of the prong. Each barb is adapted to fixedly embed in the interior of a panel to which the fastener is affixed.