Flush Blind Fastener Head for Non-Rotating Surface-Safe Installation
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Solution Overview
Problem
Blind fasteners face challenges in securely fastening workpieces when access to the blind side is difficult or impossible, as existing solutions often require complex setups or risk damaging the workpieces during installation.
Innovation Solution
A fastener system comprising a sleeve with a planar head and a pin member, where the fastener installation tool uses frictional engagement and protrusions to prevent the sleeve from rotating relative to the workpiece, ensuring secure installation without damaging the surface, and a breakneck portion that fractures to provide a flush configuration post-installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sleeve head includes a recess for engagement with the installation tool, then the sleeve can be securely held during installation, but the surface finish is compromised and the head is no longer substantially flat
Solution Approach 1:
The engagement feature is segmented into multiple discrete protrusions (at least three) distributed around the sleeve head circumference, rather than a single recess. This segmentation allows the installation tool to engage multiple points on the flat surface, providing secure holding without requiring a recess that would compromise the overall flat surface finish.
Solution Approach 2:
Instead of providing a recess in the sleeve head for the installation tool to engage (traditional approach), the invention inverts the approach by providing protrusions on the installation tool that engage with the flat surface of the sleeve head. This inversion allows the sleeve head to maintain its substantially flat surface while still providing secure engagement during installation.
2Object-affected harmful factors
If the installation tool uses frictional engagement with the planar surface, then the surface is not damaged, but the prevention of rotation during installation is insufficient
Solution Approach 1:
The invention merges two approaches: frictional engagement (to prevent surface damage) and mechanical interlocking via protrusions (to prevent rotation). The protrusions on the installation tool engage with the flat surface of the sleeve head, combining the benefits of friction-based surface protection with positive mechanical engagement for reliable rotation prevention during installation.
3Reliability
If the protrusions are made of hard material, then they can effectively engage the sleeve surface, but the installation tool becomes more complex
Solution Approach 1:
The installation tool uses local quality by making only the protrusions (the specific engagement points) from hard material, while the rest of the tool body can be made from softer or less expensive materials. This localized application of hard material provides effective engagement with the sleeve surface without requiring the entire tool to be complex or made from high-performance materials throughout.
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 effectively secures workpieces together by preventing rotation during installation and providing a flush finish, enhancing the stability and aesthetic appeal of the assembly while minimizing damage to the workpieces.
Implementation Method 1
The at least one protrusion is configured to engage and removably embed within the first planar surface of the head of the sleeve to prevent the sleeve from rotating relative to the workpiece
Implementation Method 2
the external thread of the pin member is configured to threadedly engage the internal thread of the sleeve
Data Source
AI summary
A system includes a fastener and a fastener installation tool. The fastener includes a sleeve having a tubular portion with an internal threaded portion having an internal thread, and a head. The head of the sleeve is configured to be installed in an accessible hole in a workpiece having a surface. The fastener includes a pin member having a threaded portion with an external thread. The pin member is disposed within the sleeve and the external thread of the pin member is configured to threadedly engage the internal thread of the sleeve. The fastener installation tool includes a nosepiece having a face configured to engage the head of the sleeve without the face contacting the surface of the workpiece.