Reusable Blind Fastener With Elastic Expansion Locking
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Solution Overview
Problem
Existing blind fasteners are typically permanent and non-reusable, relying on permanent deformation, which limits their application to one-time use and fails to provide a strong non-permanent joint.
Innovation Solution
A reusable blind fastener design incorporating a bushing, nut, tail, receiver, and expansion device with a discontinuous exterior surface that undergoes selective elastic deformation when engaging a screw, allowing for repeatable and strong non-permanent joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If permanent deformation is used to create a strong joint, then joint strength is improved, but reusability deteriorates
Solution Approach 1:
The patent changes the deformation parameter from permanent to elastic, allowing the expansion device to deform reversibly. This enables the fastener to be installed and removed multiple times while maintaining joint strength through controlled elastic deformation of the discontinuous exterior surface.
Solution Approach 2:
The expansion device transitions from a static permanent deformation mechanism to a dynamic elastic deformation mechanism. The discontinuous exterior surface allows controlled elastic expansion during installation and recovery during removal, enabling reusable operation while maintaining strong joint formation.
2Adaptability or versatility
If repeatable plastic deformation is used, then reusability is improved, but fatigue and stress concentration failures worsen
Solution Approach 1:
The patent changes the deformation type from plastic to elastic, fundamentally altering the material behavior during repeated cycles. Elastic deformation avoids permanent damage accumulation and stress concentration that lead to fatigue failure, enabling reliable reusable operation.
Solution Approach 2:
The discontinuous exterior surface design provides stress distribution features that prevent stress concentration before fatigue can occur. The geometry is configured to distribute loads evenly during elastic deformation cycles, preventing the initiation of fatigue cracks.
3Adaptability or versatility
If a discontinuous exterior surface is used, then elastic deformation capability is improved, but manufacturing complexity worsens
Solution Approach 1:
The exterior surface is segmented into discontinuous regions rather than being continuous. This segmentation enables localized elastic deformation in specific areas while maintaining structural integrity, achieving the desired elastic behavior through geometric division rather than complex material properties.
Solution Approach 2:
Different regions of the expansion device have different geometric properties - the discontinuous exterior surface areas are designed for elastic deformation while other areas maintain structural strength. This local differentiation achieves elastic deformation capability without requiring complex materials throughout the entire component.
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 reliable and repeatable engagement and disengagement of the fastener, preventing removal while ensuring durability and avoiding fatigue and stress concentration failures, making it suitable for multiple uses.
Implementation Method 1
The expansion device having an exterior surface that is discontinuous and configured for selective elastic deformation when engaging a portion of the screw
Data Source
AI summary
A reusable blind fastener including a bushing, a nut, a tail, a receiver, an expansion device, and a screw. The expansion device having an exterior surface that is discontinuous and configured for selective elastic deformation when engaging a portion of the screw.