Sleeved Collet Fastener With Free-Rotating Stud for Shear Loads
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Solution Overview
Problem
Previous blind fasteners are susceptible to shear stresses, leading to damage and failure of flexible arms, making them difficult to remove and resulting in permanent deformation, and the stud can become stuck due to deformed collet body fingers.
Innovation Solution
A fastener system with a sleeve enclosing a collet body, featuring cantilever legs that decouple shear stresses from the collet body, allowing the sleeve to absorb these forces, and a stud with a threaded section engaging with the collet body or sleeve, enabling easy installation and removal without binding, and a reduced diameter section for free rotation to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the collet body is exposed in previous fasteners, then the flexible arms can directly engage with structures, but the collet body becomes susceptible to shear stresses leading to damage and failure
Solution Approach 1:
The collet body is nested within the sleeve, with the sleeve providing external protection while the collet body maintains its engagement function. This nested configuration shields the collet body from direct shear stress exposure while preserving its ability to engage with structures through the sleeve's opening.
Solution Approach 2:
The sleeve acts as an intermediary between the external environment and the collet body, absorbing and distributing shear stresses before they reach the collet body. This mediator structure protects the flexible arms from direct shear loading while still allowing the fastener to function properly.
2Ease of manufacture
If the flexible arms are positioned at maximum distance from the shear force vector, then insertion is easier, but they resist very little shearing force
Solution Approach 1:
The sleeve serves as a mediator that transfers shear forces from the external environment to the collet body in a controlled manner. This allows the flexible arms to maintain their optimal insertion positioning while the sleeve handles the brunt of shear force resistance, preventing direct exposure to damaging shear stresses.
3Force
If the stud is tightly threaded into the collet body, then clamping force increases, but the stud becomes difficult to remove and may become stuck
Solution Approach 1:
The sleeve acts as an intermediary between the stud and the collet body, allowing the stud to thread into the assembly without directly engaging the flexible arms. This mediator structure enables sufficient clamping force transmission while preventing the stud from becoming stuck, as the sleeve provides a smoother, more controlled threading interface.
4Productivity
If the collet body fingers are exposed, then they can directly clamp structures, but they suffer permanent deformation and degradation from shear stress
Solution Approach 1:
The collet body is nested within the protective sleeve, allowing the fingers to maintain direct clamping contact with structures while the sleeve provides external protection from shear stresses. This nested arrangement preserves clamping efficiency while extending service life by shielding the fingers from degrading shear forces.
Solution Approach 2:
The sleeve functions as a protective intermediary that absorbs external shear stresses before they reach the collet body fingers. This allows the fingers to continue their clamping function efficiently while the sleeve bears the brunt of shear loading, preventing permanent deformation and extending the fastener's operational life.
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 system increases the longevity of the fastener by protecting the collet body from shear stresses and abrasive wear, allowing for efficient clamping and unclamping, and reducing the likelihood of degradation.
Implementation Method 1
a threaded section engaging with an interior threaded section in at least one of the collet body and/or the sleeve
Implementation Method 2
the longevity of the fastener described herein, when compared to previous fasteners that suffer from shear stresses degrading the ability of the cantilever leg to flex or retain its memory shape
Data Source
AI summary
A fastener system shifting shear stresses away from a collet body and provides clamping action to targeted structures. The fastener system includes feet in the collet body that mate with openings in a sleeve at least partially surrounding the collet body. The sleeve or the collet body includes interior threads that engage with a stud that is configured to extend through the collet body and bend the feet such that they project outward from the sleeve openings in an engaged configuration.