Pressure Lock Fastener With Expandable Flanges for Blind Panel Fastening
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Solution Overview
Problem
Conventional fastening devices require access to both sides of the panels for installation, which is not feasible in many manufacturing, construction, and assembly scenarios where both sides are not accessible.
Innovation Solution
The pressure lock retention fastener system includes an insert, a threaded collet with expandable flanges, and a screw that pushes the flanges outward to seat against the second panel, allowing for top-down installation and secure fastening without needing access to both sides, along with anti-rotation features to prevent spinning and false lock engagements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional fastening devices are used, then secure fastening of panels is achieved, but access to both sides of panels is required for installation
Solution Approach 1:
The fastening system is divided into separate functional components: an insert with internal threads installed in the first panel, and a collet with expandable flanges that engages the insert. This segmentation allows the fastener to be installed from one side only, as the collet expands to lock onto the insert without requiring access to the other side of the panel.
Solution Approach 2:
The collet is designed to slide over the insert and nest within the panel thickness, with the expandable flanges containing the insert when expanded. This nested configuration enables the fastening mechanism to be contained within the panel structure, allowing installation from a single side while maintaining secure fastening.
2Ease of operation
If expandable flanges are used to enable top-down installation, then single-side installation is achieved, but anti-rotation features are needed to prevent spinning
Solution Approach 1:
The insert includes asymmetric features such as a flat spot or keyway that corresponds to a protrusion on the collet. This asymmetric geometry prevents the collet from rotating freely on the insert, ensuring proper orientation during installation and operation while maintaining the top-down installation capability.
3Adaptability or versatility
If threaded collet with expandable flanges is used, then reusable fastening is achieved, but thread binding risk increases
Solution Approach 1:
The threading function is extracted from the traditional bolt-nut configuration and relocated to the insert, which remains stationary in the panel. The collet engages this stationary threaded insert without requiring threads on moving parts, eliminating the risk of thread binding that occurs when threads are subjected to repeated expansion and contraction forces.
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, top-down installation of panels without requiring access to both sides, providing a reusable and customizable solution for various materials and applications, including aerospace and construction, with enhanced load handling capabilities and reduced risk of thread binding.
Implementation Method 1
The screw exerts a force and pushes the expandable flanges outward as screw rotation drives the screw into the threaded collet
Implementation Method 2
Ridge locks of the expandable flanges seat up against the second panel effective to fasten the panels together
Data Source
AI summary
In implementations of a pressure lock retention fastener, the fastener assembly includes an insert sized for insertion into a fastener hole in a first panel. The fastener assembly has a threaded collet sized to slide in the insert and has expandable flanges that extend below the insert. The expandable flanges are sized for insertion into an aligned hole in a second panel. The fastener assembly also includes a screw installable through the insert to engage the threaded collet. The screw exerts a force that pushes the expandable flanges outward as screw rotation drives the screw into the threaded collet, and ridge locks of the expandable flanges seat up against the second panel effective to fasten the panels together. In implementations, a plate is installable between the panels with slotted holes having anti-rotation tabs that prevent a fastener assembly from spinning in the panel holes.