Folding Stair Construction for Motor Vehicle Entry

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Solution Overview

Problem

Elderly, smaller, and handicapped individuals face difficulties when boarding or exiting buses due to the high first step of the boarding stairs, which often exceeds 40 cm above ground level, and existing folding stair solutions require complex mechanisms and frequent unfolding, posing challenges for easy access.

Innovation Solution

A folding stair construction with a Z-shaped surface element and mounting device that allows the stair to pivot 180°, providing additional stepping surfaces when extended and functioning as two superimposed steps when folded, with a thickness of less than 8mm for enhanced stability and anti-slip features, allowing easy retrofitting to motor vehicles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a footplate is pivotably mounted on the boarding steps to reduce entry height, then the entry height is reduced when unfolded, but the mechanism becomes relatively complex and the footplate cannot unfold under the vehicle sill level

Engineering Contradiction:
Improveentry heightVSAvoidpivoting mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The folding stair is divided into multiple steps (first step, second step, third step) connected by stair step offsets. Each step can be independently positioned, allowing the structure to achieve the required entry height reduction without complex mechanisms. The segmentation enables the stair to adapt to different mounting positions including under the vehicle sill level.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a vertical dimension to the solution by stacking multiple steps vertically rather than using a single large footplate. The stair step offsets create vertical separation between steps, allowing the structure to achieve height reduction through vertical arrangement rather than horizontal pivoting, eliminating the need for complex pivoting mechanisms.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If a single thick surface element is used for the folding stair to ensure stability, then stability is improved, but manufacturing and installation become more difficult

Engineering Contradiction:
ImprovestabilityVSAvoidmanufacturing and installation
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The surface element is segmented into multiple thinner components (first surface element, second surface element, third surface element) corresponding to different steps. This segmentation makes each component easier to manufacture and install while maintaining overall stability through the stacked arrangement. The thinner individual elements can be more easily formed and positioned.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The folding stair uses a composite structure combining multiple surface elements with different functions. The first surface element provides the climbing surface, while the second and third surface elements form the stair step offsets and structural support. This composite approach allows each element to be optimized for its specific function, improving manufacturability while maintaining stability.

Inventive Principle:
Principle #40Composite materials

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 solution significantly reduces the entry height, facilitates easier access by providing additional stepping surfaces, and maintains stability while being easy to use and maintain, addressing the accessibility issues for vulnerable groups.

Implementation Method 1

a mounting device by means of which the folding stair can be mounted on the motor vehicle and about which the folding stair can be appropriately pivoted

Methodology Applied
Scientific EffectPivoting: Hinge

Data Source

PatentEP2845768B1Folding stair structure for a motor vehicle comprising entry steps
Publication Date: 2016.04.06 MAN TRUCK & BUS SE
  • EP2845768B1 patent drawingFigure 1~2
  • EP2845768B1 patent drawingFigure 3~4
  • EP2845768B1 patent drawingFigure 5~6

AI summary

The invention relates to a folding stair construction (1) for a motor vehicle (100), preferably a bus, which has an entry stair (101). The folding stair construction (1) comprises a folding stair (2) and a mounting device (3) by means of which the folding stair (2) can be mounted to the motor vehicle (100) and about which the folding stair (2) is preferably pivotable. The folding stair (2) is characterized in particular by the fact that it comprises at least two steps (5, 6) connected to each other by a step offset (4).