Rail Fastener Elastomeric Layer Reduces Stress
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Solution Overview
Problem
The design of direct fixation fasteners for special trackwork areas in passenger railroads requires flexibility and geometric adjustability, which increases manufacturing complexity and costs due to the need for multiple tools and unique hold-down clip positions, while also needing to maintain high resilience and structural stability.
Innovation Solution
A high resilient special trackwork direct fixation fastener design featuring a top plate with slotted holes, a metal structural channel bottom plate with angle bars, and an elastomeric layer between the plates and angle bars, allowing for adjustable length and reduced manufacturing complexity using off-the-shelf materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If special trackwork plates are designed in different lengths and with varying hold-down clip positions to accommodate track geometry, then geometric adaptability is improved, but manufacturing complexity and cost increase due to requiring multiple tools
Solution Approach 1:
The patent applies universality by designing a single standardized plate geometry that can serve multiple track configurations. The top plate and bottom plate maintain consistent dimensions and features across all fastener variants, allowing the same plate designs to be used in different lengths and configurations without requiring unique plate patterns for each application.
Solution Approach 2:
The patent implements dynamics through movable and adjustable components. The hold-down clips are designed to be repositionable along the plate edges, and the fastener assembly allows for flexible configuration to accommodate various track geometries. This dynamic adjustability enables a single plate design to adapt to different installation requirements without requiring multiple specialized plate designs.
2Object-affected harmful factors
If high resilience fasteners are designed to provide higher deflection under load for noise and vibration mitigation, then noise and vibration mitigation is improved, but stress in the product increases
Solution Approach 1:
The patent employs composite materials by combining metal plates (top plate and bottom plate) with an elastomeric layer. This composite structure allows the rigid metal components to provide structural strength and load-bearing capacity, while the elastomeric layer provides the necessary flexibility and resilience for noise and vibration mitigation. The composite design distributes stresses appropriately between the stiff metal elements and the compliant elastomeric material.
Solution Approach 2:
The patent applies local quality by concentrating the resilient properties in specific locations within the fastener assembly. The elastomeric layer is positioned strategically between the top plate and bottom plate to provide localized cushioning and deflection where needed for noise and vibration control, while the metal plates maintain their full strength in load-bearing regions. This localized application of different material properties optimizes both resilience and strength.
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
This design reduces manufacturing complexity and costs while maintaining high resilience and adjustability, effectively addressing the challenges of special trackwork requirements by enabling the production of fasteners in various lengths with consistent width, thus improving geometric adaptability and reducing stress.
Implementation Method 1
an elastomeric layer disposed between the top plate and the bottom plate, between the top plate and angle bars and between the angle bars and the spaced-apart side walls
Data Source
AI summary
A direct fixation fastener comprising: a top plate; a bottom plate made of metal structural channel providing two spaced-apart side walls, wherein the bottom plate has a first end and a second end and wherein each of the first and second ends terminate in a first flat edge section and a second flat edge section, respectively, without spaced-apart side walls; first and second angle bars, wherein the first angle bar is attached to the first flat edge section and the second angle bar is attached to the second flat edge section; and an elastomeric layer disposed between the top plate and the bottom plate, between the top plate and angle bars and between the angle bars and the spaced-apart side walls.