Fold Out Ramp Actuator Deployment Mechanism
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Solution Overview
Problem
Fold out ramps for vehicles face challenges such as requiring more torque for longer ramps, difficulty in manual operation, and obstacles created by the stowed ramp depression in the vehicle floor, which affects accessibility and safety for wheelchair-bound passengers.
Innovation Solution
A ramp assembly with a rotational movement mechanism that includes an actuator applying rotational force to drive the ramp through deployment phases, allowing for a longer ramp surface with reduced slope and a compact operating system, ensuring the ramp surface is coplanar with the vehicle floor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the ramp length is increased to reduce the slope angle for better accessibility, then the ramp becomes heavier and requires more torque for deployment, but manual operation becomes difficult and power sources may fail
Solution Approach 1:
The ramp is divided into multiple segments that can fold relative to each other. This segmentation allows the ramp to achieve a longer extended length while maintaining a compact folded size, and enables the deployment force to be applied more efficiently to overcome the torque requirement without needing excessive power
Solution Approach 2:
The ramp segments are designed to nest within each other when folded, similar to a nested doll structure. This nesting approach maximizes the ramp length when deployed while minimizing the space and structural requirements when stowed, effectively resolving the contradiction between length and torque requirements
2Ease of operation
If a depression is created in the vehicle floor to store the retracted ramp, then the ramp can be stowed horizontally, but the depression creates an obstacle for wheelchair passengers transitioning into the vehicle
Solution Approach 1:
The harmful depression in the vehicle floor is extracted and eliminated by redesigning the stowage mechanism. The ramp is configured to fold vertically against the vehicle interior surfaces rather than creating a floor depression, removing the obstacle while preserving stowage functionality
Solution Approach 2:
Instead of folding the ramp horizontally into a floor depression, the ramp is inverted to fold vertically against the vehicle's interior surfaces. This inversion eliminates the floor depression obstacle while maintaining effective ramp stowage capability
3Reliability
If large electric motors, pneumatic devices, or hydraulic actuators are used to satisfy the increased torque requirement, then the ramp can be deployed reliably, but the system complexity increases and manual operation is impossible without disengaging the drive mechanism
Solution Approach 1:
The ramp deployment mechanism is designed to be self-servicing through a spring-loaded counterbalance system that automatically compensates for the ramp's weight. This eliminates the need for complex electric motors, pneumatic devices, or hydraulic actuators, while still providing reliable deployment and allowing manual operation without disengagement
Solution Approach 2:
A spring-loaded counterbalance mechanism is implemented to offset the weight of the ramp during deployment. The counterweight system provides mechanical assistance that reduces the effort needed for manual operation while ensuring reliable deployment, without requiring complex powered drive mechanisms
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 provides a longer, more accessible ramp surface with reduced slope, enhancing mobility and safety for wheelchair-bound passengers by allowing for efficient deployment and stowage without manual power assistance, and eliminating obstacles from the stowed ramp depression.
Implementation Method 1
An actuator is operably connected to the ramp portion and selectively applies a rotational force to the ramp portion to drive the ramp portion through a deployment motion
Data Source
AI summary
A ramp assembly provides a transition surface from a vehicle floor to an alighting surface. The ramp assembly includes a ramp portion that rotates between a stowed position and a deployed position. A panel is rotatably coupled to the ramp portion about a first axis. The ramp assembly further includes an actuator that provides a rotational force to the ramp portion that drives the ramp portion through a deployment motion. The deployment motion includes a first phase during which the rotational force rotates the ramp portion about the first axis. The deployment motion further includes a second phase during which the rotational force moves the first axis in a downward direction.