Railway Car Cushioning Apparatus for Draft and Buff Loads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cushioning devices for railway cars fail to effectively absorb both draft and buff loads over a range of impact speeds, often transmitting unacceptably large forces and being prone to leakage, buckling, and over-compression, which can lead to permanent deformation and misalignment.
Innovation Solution
A cushioning apparatus with aligned elastomeric units positioned between a coupler-receiving member and a yoke, featuring separate stacks for draft and buff loads, where the plates are designed to prevent over-compression by nesting and metal-to-metal contact, ensuring alignment and efficient energy absorption in a compact format.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional frictional draft gear with elastic elements is used, then the device can absorb some draft and buff loads, but unacceptably large forces are transmitted to the railway car
Solution Approach 1:
The cushioning device is divided into separate draft and buff cushioning elements that operate independently. The draft cushioning element absorbs draft loads through compression of elastomeric pads between the draft gear and yoke, while the buff cushioning element absorbs buff loads through compression of elastomeric pads between the coupler follower and yoke. This segmentation allows each element to be optimized for its specific load type, effectively limiting force transmission to the railway car.
Solution Approach 2:
The invention uses elastomeric materials with specific durometer ratings (e.g., 60-90 Shore A) and varying pad thicknesses to achieve different cushioning characteristics. By changing the physical parameters of the elastomeric pads (density, thickness, durometer), the device can effectively absorb both draft and buff loads across different impact conditions while limiting force transmission.
2Force
If hydraulic cushioning units are used, then more force can be dissipated, but the devices are prone to leakage
Solution Approach 1:
The invention replaces complex hydraulic systems with simple elastomeric pad assemblies that are inherently leakage-free. These elastomeric cushions are designed as maintenance-free, disposable components that can be easily replaced when worn, eliminating the leakage problems associated with hydraulic seals and connections while maintaining high force dissipation capability.
Solution Approach 2:
The invention substitutes hydraulic mechanical systems with purely elastomeric mechanical cushioning elements. The elastomeric pads deform under load to absorb energy, replacing the hydraulic fluid compression and seal mechanisms, thereby eliminating leakage issues while maintaining effective force dissipation.
3Adaptability or versatility
If separate draft and buff cushioning elements are coupled and fitted into the draft gear pocket, then both loads can be absorbed, but the apparatuses are prone to buckling
Solution Approach 1:
The draft and buff cushioning elements are nested within the yoke structure, with each element positioned in its own dedicated space. The draft cushioning element is positioned between the draft gear and the yoke's front wall, while the buff cushioning element is positioned between the coupler follower and the yoke's rear wall. This nested arrangement prevents buckling by ensuring each element remains properly aligned and supported during operation.
Solution Approach 2:
The invention uses asymmetric positioning and sizing of the draft and buff cushioning elements within the yoke. The draft element is positioned forward and the buff element is positioned rearward, with different pad dimensions optimized for their respective load types. This asymmetric design prevents buckling by providing appropriate structural support and alignment for each element's specific loading conditions.
4Ease of manufacture
If cushioning elements are positioned forward of the back wall of the yoke, then installation is simplified, but the device occupies more space and may cause misalignment
Solution Approach 1:
The invention utilizes the vertical dimension within the yoke's center sill pocket to position the cushioning elements. The elastomeric pads are arranged vertically between the draft gear/coupler follower and the yoke's front and rear walls, respectively. This vertical arrangement allows both draft and buff cushioning elements to be positioned within the available space without protruding forward, simplifying installation while preventing misalignment.
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 apparatus effectively limits force transmission to the railway car across various impact speeds, preventing over-compression and buckling, while maintaining alignment and absorbing both draft and buff loads efficiently, with minimal permanent deformation and improved installation in standard pockets.
Implementation Method 1
a first stack of elastomeric units positioned between the coupler-receiving member and the vertical wall of the yoke, said first stack being compressed by draft and buff loads on the coupler; a second stack of elastomeric units positioned between the front buff plate and the rear buff plate, said second stack being compressed in response to buff loads on the coupler
Implementation Method 2
A piston-like element frictionally received in the housing absorbs buff loads transmitted via a coupler follower which moves inside the yoke
Data Source
AI summary
An improved selective travel cushioning device for a railway car is responsive to both draft and buff loads on the coupler, fitting into a standard cushioning unit pocket with little or no reconfiguration of the sill required, while limiting wear on elastic members in the cushioning unit and exhibiting high energy absorption.