Three-Point Bearing Rail Vehicle Step
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Solution Overview
Problem
Existing boarding aids for rail and motor vehicles face issues such as tilting and damage due to asymmetric loading, and excessive wear on rolling elements or sliding surfaces, which can lead to unintended lifting and damage.
Innovation Solution
The boarding aid features rolling elements or sliding surfaces positioned in exactly three spaced-apart support areas arranged in a triangle, with each support area forming a cluster of rolling elements or sliding surfaces, and force introduction points that distribute load statically, reducing the risk of tilting and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If four spaced-apart rollers are used to guide the running board, then the running board is prevented from tipping over, but the mounting becomes statically indeterminate leading to unpredictable forces and potential lifting of carrying areas
Solution Approach 1:
The patent removes one roller from the four-roller configuration, extracting the excess constraint that causes static indeterminacy. By using exactly three rollers arranged in a triangle, the system maintains stability while achieving static determinacy, ensuring predictable force distribution at each roller position.
2Area of stationary object
If multiple rolling elements are distributed across the running board, then coverage is improved, but unintended lifting of carrying areas occurs leading to excessive load on other areas
Solution Approach 1:
The patent concentrates the three rollers at specific triangular positions along the running board rather than distributing them uniformly. This local placement strategy ensures that each roller bears a predictable portion of the load without causing lifting at other locations, as the triangular arrangement provides stable geometric distribution of support points.
3Adaptability or versatility
If the running board is loaded asymmetrically, then normal operation continues, but the running board tilts and rolling elements or sliding surfaces become damaged
Solution Approach 1:
The patent deliberately uses an asymmetric triangular arrangement of three rollers rather than a symmetric configuration. This asymmetric geometry naturally accommodates asymmetric loading conditions by providing stable support points that prevent tilting, as the triangle's inherent geometric stability distributes forces predictably regardless of load symmetry.
4Strength
If hardened surfaces are used for rolling elements, then durability is improved, but they can be destroyed by excessive load or impact
Solution Approach 1:
The patent prevents excessive loads from reaching the hardened rolling elements by using the three-roller triangular configuration that eliminates static indeterminacy and unpredictable force spikes. This design cushioning approach prevents impact loads that could destroy hardened surfaces, allowing the use of hard materials without the risk of catastrophic failure from unexpected load surges.
Data Source
AI summary
The invention relates to an entry aid (1) for a rail vehicle or a motor vehicle, comprising a step (2) which is movably supported on rolling elements (30..33) and/or sliding surfaces (16), and a drive (6) which is coupled to the step (2) for extending and retracting the step (2). The rolling elements (30..33)/sliding surfaces (16) are positioned in exactly three support regions (40..43) at a distance from one another and arranged in a triangle. Alternatively the rolling elements (30..33)/sliding surfaces (16) can be arranged on a plurality of rockers (20), and bearing points (21) of the rockers (20) can be positioned in exactly three support regions (40..43) at a distance from one another and arranged in a triangle.