Low Floor Suspension Vehicle Multi-Joint Design

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Solution Overview

Problem

Current low-floor vehicles with conventional wheel diameters and chassis technology face challenges in achieving low entry heights suitable for wheelchair users without additional aids like lifts or folding ramps, leading to high maintenance costs and operational wear due to complex wheel and drive arrangements.

Innovation Solution

A multi-articulated vehicle design with a horizontal intermediate level and strategically placed transverse and longitudinal ramps with controlled inclines, allowing for a wide, flat entry area directly adjacent to the driver's cab with an entry height of less than 250 mm, enabling unrestricted wheelchair access without additional aids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If conventional wheel and drive arrangements are used to achieve low entry heights, then entry height is reduced, but device complexity and maintenance costs increase

Engineering Contradiction:
Improveentry heightVSAvoidwheel and drive arrangement complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The vehicle floor is segmented into different levels: a first low floor level for passenger seating and a second even lower level for the multifunctional area. This segmentation allows the multifunctional area to be accessed at a lower entry height without requiring complex wheel and drive arrangements, as the low entry height is achieved through the stepped floor design rather than specialized propulsion systems.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If additional aids like lifts or folding ramps are installed to enable wheelchair access, then wheelchair accessibility is improved, but device complexity and maintenance costs increase

Engineering Contradiction:
Improvewheelchair accessibilityVSAvoidadditional aids complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The second floor level is designed to be at a lower elevation than the first floor level, creating an equipotential surface that is naturally accessible to wheelchair users. By positioning the multifunctional area on this lower level and providing direct access through the front door, the design eliminates the need for lifts or folding ramps, as wheelchair users can access the area without encountering height barriers that would require mechanical assistance.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The horizontal intermediate level acts as an intermediary structure that mediates between the conventional first floor level and the ground platform. This intermediate level provides a stable, accessible surface for wheelchair users to reach the multifunctional area without requiring active mechanical aids like lifts or ramps, thereby simplifying the overall system while maintaining accessibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If ramps with high gradients are used to overcome floor level differences, then floor level coordination is improved, but ease of operation for wheelchair users deteriorates

Engineering Contradiction:
Improvefloor level coordinationVSAvoidwheelchair accessibility
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

Instead of raising the multifunctional area to match the first floor level (conventional approach), the design inverts the approach by lowering the multifunctional area to a second floor level below the first floor. This inversion eliminates the need for ramps with high gradients, as the natural floor level difference creates a barrier-free access path for wheelchair users rather than a barrier.

Inventive Principle:
Principle #13The other way round (Inversion)

4Stability of the object's composition

If level control systems are implemented to maintain constant entry level, then coordination with platform heights is improved, but device complexity increases

Engineering Contradiction:
Improveentry level constancyVSAvoidlevel control system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The vehicle's floor design inherently provides the level coordination function through its fixed two-level structure. The first floor level and second floor level are maintained at fixed relative heights, with the second level providing automatic accessibility to wheelchair users. This self-service design eliminates the need for active level control systems, as the geometric configuration of the floor itself ensures consistent coordination with platform heights without requiring mechanical adjustment.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2733039B2Low floor suspension vehicle in multi-joint construction
Publication Date: 2023.08.02 BOMBARDIER TRANSPORTATION GMBH
  • EP2733039B2 patent drawingFigure 1
  • EP2733039B2 patent drawingFigure 2
  • EP2733039B2 patent drawingFigure 3

AI summary

The vehicle i.e. low-floor landing gear vehicle (1), has landing gears with axle bases, and a front entrance region (4) provided with low entrance height of about 250 mm. A multi-functional surface (5) is arranged between a driver's cab (2) and an axis (3) of the vehicle located in the front entrance region. The surface is formed with a horizontal intermediate level with a predominantly horizontal plane, transverse- and longitudinal ramps and a wedge region. The ramps are inclined from the axis towards the intermediate level or from the level towards the entrance region.