Pivotable Retention Gate for Wheelchair Lift Safety
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Solution Overview
Problem
Existing wheelchair lift systems for mobility vehicles lack an effective and safe mechanism to prevent users from exiting the lift platform at elevated positions, posing a risk of accidents and ensuring secure access.
Innovation Solution
A safety barrier system comprising a pivotable retention gate and roll stop plate mechanism that aligns with the lift platform's movement, allowing secure access and preventing unauthorized exit when the platform is elevated, utilizing a latch assembly and linkage system to control the gate's position relative to the platform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed barrier is used on the lift platform, then user safety is improved, but the barrier interferes with wheelchair access when the platform is at ground level
Solution Approach 1:
The barrier is designed as a dynamic structure that pivots between a vertical barrier position (when platform is elevated) and a horizontal stowed position (when platform is at ground level). This allows the barrier to adapt its configuration based on platform position, providing safety when needed and not interfering with access when the platform is level with the ground.
Solution Approach 2:
The barrier transitions from occupying the vertical dimension (as a barrier) to the horizontal dimension (when stowed parallel to the platform surface). This dimensional transformation allows the same structure to serve dual purposes: blocking access when elevated and allowing access when level.
2Reliability
If a pivotable gate is used that moves with the platform, then safety is maintained during elevation, but the gate mechanism becomes more complex
Solution Approach 1:
The gate mechanism is merged with the lift platform structure itself. The barrier is mounted to the platform and moves with it, combining the platform's vertical motion with the barrier's positioning function. This eliminates the need for separate complex actuation systems while maintaining safety during elevation.
Solution Approach 2:
The lift platform structure serves multiple functions: it provides the lifting surface and simultaneously acts as the mounting structure for the safety barrier. The barrier leverages the platform's motion for its own positioning, making the system more efficient and less complex.
3Reliability
If the gate is restricted from pivoting only when latched, then safety is ensured, but the operation becomes less flexible
Solution Approach 1:
The latch assembly provides mechanical feedback that automatically restricts gate pivoting when engaged. The system monitors its own state through the physical connection between the latch and gate, ensuring safety constraints are enforced while allowing free operation when the latch is disengaged.
Data Source
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AI summary
A lift platform assembly coupled to a floor and capable of transitioning a lift platform between a stow position and a ground level position. The lift platform assembly has one or more arms coupling the lift platform to the floor, a gate mount coupled to the lift platform at an outboard end, a retention gate coupled to the gate mount at a first terminus, and a mount pivot axis defined through the gate mount and parallel to a lift platform plane. The retention gate pivots about the mount pivot axis as the lift platform assembly transitions from the ground level position to the stow position.