Binding Barrel Fastener Expansion for Multi-Substrate Interference Fit
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Solution Overview
Problem
Current binding barrel fasteners are not suitable for interference fit installations in workpieces with multiple substrates, as they can cause delamination and damage, and do not provide effective electromagnetic energy protection.
Innovation Solution
A fastener system comprising a binding barrel member with a cylindrical barrel body, a counterbored and threaded central bore, and a barrel flange, combined with a bolt member that causes radial expansion of the binding barrel member to create an interference fit within the workpiece, while also providing electromagnetic protection through conductive coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If current binding barrel fasteners are installed with interference fit, then joining strength is improved, but delamination and damage to substrates occur
Solution Approach 1:
The fastener system divides the joining function into two separate components: a binding barrel member installed in a countersink cavity and a separate bolt member that engages with it. This segmentation allows the binding barrel to be pre-installed without interference fit, avoiding substrate damage, while the bolt member provides the securing function through threaded engagement.
Solution Approach 2:
The binding barrel member acts as an intermediary component between the substrate and the bolt member. It is pre-installed in the countersink cavity and provides a threaded interface for the bolt member, enabling secure joining without requiring interference fit installation that would damage the substrates.
2Object-affected harmful factors
If binding barrel fasteners are used for electromagnetic protection, then electromagnetic energy protection is provided, but they are not suitable for interference fit installations
Solution Approach 1:
The fastener system segments the electromagnetic protection function from the joining function. The binding barrel member with conductive coating provides electromagnetic protection, while the separate bolt member provides the securing function. This allows electromagnetic protection without requiring interference fit installation.
Solution Approach 2:
The system changes the installation parameter from interference fit to countersink cavity installation. The binding barrel member is installed in a countersink cavity rather than through interference fit, allowing electromagnetic protection functionality to be maintained while adapting to substrate types that cannot tolerate interference fit installation.
3Device complexity
If a single fastener component is used, then device complexity is reduced, but the ability to join multiple substrates without delamination is limited
Solution Approach 1:
The fastener system uses two components (binding barrel member and bolt member) to reliably join multiple substrates. The binding barrel member is pre-installed in the countersink cavity, and the bolt member is subsequently engaged to secure the substrates. This segmentation enables reliable multi-substrate joining without the delamination issues that would occur with a single interference fit fastener.
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 system effectively joins multiple substrates of a workpiece with an interference fit, preventing delamination and damage, while also providing protection against electromagnetic effects.
Implementation Method 1
The cylindrical barrel body includes an outer barrel surface with a lubricious coating
Implementation Method 2
As the bolt member becomes fully engaged with the binding barrel member, the bolt member is configured to cause radial expansion of the binding barrel member
Implementation Method 3
the binding barrel member is configured to provide an interference fit within the joining bore through the multiple substrates
Data Source
AI summary
A fastener system for joining substrates of a workpiece with working and blind sides includes a binding barrel and a bolt. The binding barrel includes a cylindrical body with a proximal end, a distal end, a central bore and a flange. The central bore includes a counterbored portion and a threaded portion with internal threads. The binding barrel is inserted in a joining bore from the blind side. The barrel flange limits insertion of the binding barrel. The cylindrical body includes an outer surface with a lubricious coating. The bolt includes a head portion, a threaded portion and a shank portion. The bolt is inserted in the joining bore from the working side. The threaded portion engages with the binding barrel. As the bolt becomes fully engaged, the bolt causes radial expansion of the binding barrel, and the binding barrel provides an interference fit within the joining bore.