Star-Shaped Fastener Core for Sheet Metal Panel Engagement
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Solution Overview
Problem
Existing fasteners for sheet metal panels require high extraction force and can deform the panel, leading to potential damage and reduced durability due to uneven stress distribution on the wings during snap engagement.
Innovation Solution
A fastener with a star-shaped rigid core and three curved flexible wings, where the rigid core has three small walls extending radially, allowing for better distribution of pressure and stress reduction, and a two-step molding process for manufacturing convenience and enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a flat rigid core with two curved flexible wings is used, then the force required to introduce the foot into the hole is minimized, but the resistance to extraction forces is insufficient and panel deformation occurs
Solution Approach 1:
The rigid core is segmented into a hub and three small walls extending radially, creating a star-shaped cross-section. This segmentation distributes the extraction forces across multiple contact points (three wings instead of two), increasing the overall resistance to extraction while maintaining the low insertion force characteristic
Solution Approach 2:
The core transitions from a symmetric flat shape to an asymmetric star-shaped cross-section with three radially extending small walls. This asymmetric geometry creates three non-uniformly distributed support points for the wings, optimizing both insertion ease and extraction resistance through improved force distribution
2Device complexity
If a flat rigid core with two curved flexible wings is used, then the fastener structure is simple, but panel deformation occurs due to uneven stress distribution
Solution Approach 1:
The core is divided into a hub and three radially extending small walls, creating a star-shaped cross-section. This segmentation distributes the stress from the wings across three separate contact regions on the panel, preventing concentration of stress at single points and thereby reducing panel deformation while maintaining structural simplicity
Solution Approach 2:
The small walls are positioned at specific radial locations on the hub to create localized support points. Each small wall provides localized reinforcement at critical stress zones, improving panel interaction quality and reducing deformation in specific areas without requiring a complete redesign of the entire fastener structure
3Ease of manufacture
If two curved flexible wings are used, then the manufacturing process is simple, but wing durability is reduced due to uneven stress distribution
Solution Approach 1:
The core structure is segmented into a hub and three small walls, which in turn support three curved flexible wings. This segmentation ensures that stress is distributed evenly across all three wings during operation, preventing any single wing from bearing excessive load and thereby improving overall wing durability while maintaining manufacturability through a single-piece molding process
Solution Approach 2:
The core geometry is changed from a flat shape to a star-shaped cross-section with three radially extending small walls. This parameter change in the core geometry directly affects the stress distribution parameters acting on the wings, creating more uniform stress conditions that enhance wing durability without complicating the manufacturing process
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 improved resistance to extraction forces while minimizing the force required for insertion and reducing panel deformation risks, allowing for use with thinner sheet metals and maintaining wing durability.
Implementation Method 1
each curved flexible wing being configured to bend by elastic deformation towards said rigid core to enable the snap engagement of said foot into said hole
Data Source
AI summary
The invention concerns a fastener comprising a head and a foot comprising a rigid core and three curved flexible wings each joining said rigid core along one side, having opposite a face of said core an inside surface bordered by a longitudinal edge and by a transverse edge, and having an outside surface respectively tapering towards a pointed end which is an opposite end to said head and towards said transverse edge, on respective opposite sides of an inflection plane, each said wing being configured to bend by elastic deformation towards said core; said core comprising a hub and three small walls extending radially from said hub, whereby said core is star-shaped in cross-section; and said inside surface of each said wing is bordered by a said respective small wall which is remotely opposite said longitudinal edge.