Deflectable Helix Fastener Torque Limiting
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Solution Overview
Problem
Existing fasteners used to retain heat shields near high-temperature components, such as mufflers or catalytic converters, face issues like excessive torque breaking the stud, damage to the heat shield during installation, and susceptibility to corrosion and fracture, leading to loose or vibrating heat shields.
Innovation Solution
A stamped metal fastener with a circular body, dish-shaped interior, and deflectable wings that inwardly deflect when a predetermined torque is applied, preventing over-torque and allowing the installation tool to spin freely, while apertures in the design allow fluid displacement and reduce corrosion risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If known fasteners are used to retain heat shields, then the heat shield can be secured to the vehicle panel, but excessive torque can be applied to the stud during installation, breaking off the stud
Solution Approach 1:
The fastener incorporates deflectable arms that can dynamically adjust their position during installation. When excessive torque is applied, these arms deflect inward, allowing the installation tool to spin freely and preventing stud breakage. This dynamic mechanism automatically limits torque without requiring complex control systems.
Solution Approach 2:
The deflectable arms provide self-limiting torque protection through their inherent mechanical design. The arms naturally deflect when a predetermined torque threshold is reached, eliminating the need for external torque control devices or complex installation procedures. The fastener essentially protects itself and the stud from over-torquing.
2Strength
If known fasteners are used to retain heat shields, then the heat shield can be secured, but the body or surface of the heat shield can be marred, deflected, or damaged during installation
Solution Approach 1:
The deflectable arms provide a dynamic interface between the installation tool and the fastener body. When the arms deflect, they allow the tool to spin freely rather than transmitting excessive force to the heat shield, preventing marring or deformation of the shield's surface during installation.
Solution Approach 2:
The deflectable arms act as a pre-designed cushioning mechanism that activates before damage can occur. The arms are engineered to deflect at a predetermined torque level, cushioning the system against excessive forces that would otherwise mar or damage the heat shield during the installation process.
3Reliability
If single helix threaded connections are used in fasteners, then the fastener can be installed and retained, but the connections are susceptible to corrosion and fracture under heating/cooling cycles
Solution Approach 1:
The patent applies corrosion-resistant material coatings or treatments to the threaded connections and metal components. By changing the material parameters (such as applying protective coatings or using corrosion-resistant alloys), the fastener's resistance to corrosion and thermal fatigue is enhanced, improving durability in harsh environmental conditions.
Solution Approach 2:
The fastener may incorporate composite material structures or multi-layer constructions that combine materials with different properties. This could include corrosion-resistant coatings over structural metal, or materials selected for their thermal stability and corrosion resistance, creating a composite structure that withstands both corrosion and thermal cycling.
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 effectively limits torque applied during installation, prevents stud breakage and heat shield damage, and reduces corrosion susceptibility, ensuring secure and durable attachment of heat shields.
Implementation Method 1
the first and second deflectable wings are adapted to directly contact opposed ones of multiple faces of a socket tool when the fastener is received in a socket cavity of the socket tool... rotating the socket tool until a predetermined torque value of approximately 3.0 Nm or higher is applied to the first and second deflectable wings, thereby inwardly deflecting the first and second deflectable wings
Data Source
AI summary
A fastener includes a circular shaped body having a dish-shaped interior including an inner flat plate integrally connected to and recessed with respect to an outer planar ring. Multiple connecting legs integrally connect the inner flat plate to the outer planar ring. The outer planar ring has a substantially circular perimeter. First and second deflectable wings are each integrally connected to and extend outwardly from the perimeter of the outer planar ring by first and second deflectable arms. The first and second deflectable wings directly contact opposed ones of multiple faces of a socket tool when the fastener is received in a socket cavity of the socket tool.