Lifting Platform for Wheelchair Access in High-Floor Buses
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Solution Overview
Problem
Conventional high-floor buses with side-door boarding areas and staircases are not adequately suited for wheelchair users due to limited space and steep stairs, requiring laborious assistance and disrupting the vehicle's structure with additional boarding aids like pivotable lifting platforms or stair lifts, which are costly and restrictive.
Innovation Solution
A vertical lift device with a plate-shaped lifting platform that can be moved vertically from underfloor height to the high floor level, allowing wheelchair users to access all areas within the bus without modifying the vehicle structure, and a movable stairwell with guide devices to increase platform depth, enabling flexible and safe wheelchair access and use of onboard facilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pivotable lifting platform is added on a rear axle, then wheelchair users can be lifted onto the coach, but the vehicle structure is disrupted and additional weight is added
Solution Approach 1:
The lifting function is extracted from the main vehicle structure and integrated into the existing staircase assembly. The lifting platform is formed by the staircase steps themselves when positioned horizontally, rather than adding a separate lifting mechanism to the vehicle chassis.
Solution Approach 2:
The lifting function is merged with the staircase structure. The same staircase that provides access for able-bodied passengers also serves as the lifting mechanism for wheelchair users when positioned in the horizontal loading state, eliminating the need for separate lifting equipment.
2Ease of operation
If a stair lift is used to pull wheelchair users up the stairs, then wheelchair access is enabled, but the door height must be increased to 2.5m requiring costly structural modifications
Solution Approach 1:
Instead of pulling the wheelchair up steep stairs at an angle, the staircase is inverted to a horizontal position where the wheelchair can be lifted vertically by the hydraulic cylinder. This reverses the conventional approach of vertical lifting at the door opening to horizontal lifting after the door is closed.
Solution Approach 2:
The staircase is designed as a dynamic structure that can change its position between vertical (for able-bodied passengers) and horizontal (for wheelchair users). The guide rails and support structures enable this dynamic repositioning while maintaining structural integrity.
3Device complexity
If a standard door cut-out is used for the vertical lift, then the vehicle structure remains intact, but the platform area is too narrow for wheelchair access
Solution Approach 1:
The staircase assembly is designed to move dynamically between vertical and horizontal positions. When horizontal, it extends the platform area sufficiently for wheelchair access. The guide rails ensure proper positioning and support during this dynamic transformation.
Solution Approach 2:
The platform area is extended in the longitudinal dimension by positioning the horizontal staircase assembly to protrude beyond the door opening. This creates sufficient depth for wheelchair access while maintaining a compact transverse footprint that fits within the door opening width.
4Area of stationary object
If the staircase is made movable to increase platform depth, then wheelchair access is improved, but the mechanism complexity increases
Solution Approach 1:
Guide rails act as intermediaries between the movable staircase assembly and the fixed vehicle structure. These rails provide the necessary support and constraints for the staircase to move smoothly between positions while transferring loads to the robust vehicle frame.
Solution Approach 2:
A hydraulic cylinder provides the lifting force for moving the staircase assembly between vertical and horizontal positions. This pneumatic/hydraulic actuation simplifies the mechanism by providing powerful, controlled movement without complex mechanical linkages or manual operation.
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
Enables easy, comfortable, and unencumbered wheelchair access and use of onboard facilities without structural modifications, maintaining the bus's standard design and functionality while meeting legal accessibility requirements.
Implementation Method 1
a hydraulic cylinder (23) for lifting the staircase assembly (03) with the wheelchair user (6) from the platform level into the high floor level
Implementation Method 2
The guide devices (20) each have roller guides (21) which are aligned in the direction of displacement
Data Source
Figure 1
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Figure 3
AI summary
The overland bus (1) has an entrance area (2), which is assigned to a side door and has a platform (4) in the low-floor level and a staircase (3) with multiple steps from the stair head to the high floor (5). The lift device is designed as a vertical lift. The platform is formed as a plate-shaped lifting platform and is displaced vertically from a low-floor sided initial position into a lifting position to the level of the high floor. The displacement of the platform is controlled by a motor.