Vehicle Ramp Assembly with Tilt Sensor
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Solution Overview
Problem
Fold out ramps for vehicles face challenges such as increased torque requirements due to longer lengths, difficulty in manual operation, obstacles from stowed ramp depressions, and varying deployment conditions like road crown and kneeling features, which affect ramp slope and accessibility for wheelchair-bound passengers.
Innovation Solution
A ramp assembly with a rotatable ramp portion that includes a sensor system to detect the absolute angle relative to a horizontal plane, providing an alert when the ramp reaches a predetermined angle, ensuring safe and accessible deployment regardless of vehicle tilt or surface conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If longer ramps are used to provide a more gradual slope for wheelchair accessibility, then the ramp slope becomes more gradual and accessible, but the weight of the ramp increases and more torque is required to reciprocate it between deployed and stowed positions
Solution Approach 1:
A counterbalance spring assembly is integrated into the ramp mechanism to offset the weight of the ramp. The spring applies a counterbalancing force that reduces the effort required to deploy and stow the ramp, making longer, more accessible ramps feasible without proportionally increasing the actuation torque requirement.
Solution Approach 2:
The ramp system uses a dynamic actuation mechanism with variable torque characteristics. The electric motor or actuator is sized and controlled to provide high torque during deployment and stowage operations, then reduces torque during holding, optimizing energy consumption and system size while supporting longer ramp configurations.
2Ease of operation
If longer ramps are used to provide a more gradual slope, then the ramp slope becomes more gradual and accessible, but more torque is required to reciprocate the ramp between deployed and stowed positions
Solution Approach 1:
The counterbalance spring assembly directly addresses the torque requirement by providing a mechanical advantage throughout the ramp's motion range. The spring is calibrated to compensate for the ramp's weight moment, reducing the net torque that the electric motor or actuator must generate during deployment and stowage operations.
Solution Approach 2:
The patent replaces purely mechanical actuation systems with an electric motor or actuator controlled by a controller. This allows for precise torque control, variable speed operation, and integration with sensor feedback to optimize the torque profile during ramp deployment and stowage, reducing peak torque requirements while maintaining accessibility.
3Ease of operation
If a depression is created in the vehicle floor to store the retracted ramp, then the ramp can be stowed, but the depression presents an obstacle for wheelchair passengers transitioning from the ramp to the vestibule
Solution Approach 1:
The ramp mechanism is extracted from a traditional floor-depression stowage configuration. Instead of storing the ramp in a recessed pocket in the vehicle floor, the ramp is designed to stow in a manner that minimizes floor disruption. The intermediate panel and ramp portion are configured to work together to eliminate or minimize the depression, reducing the obstacle for wheelchair passengers while maintaining stowage functionality.
4Adaptability or versatility
If the ramp is designed for typical deployment conditions, then the ramp slope is suitable under normal conditions, but the slope is adversely affected by operating conditions such as road crown, kneeling capability, and road surface deployment
Solution Approach 1:
A sensor system is integrated into the ramp mechanism to detect the actual deployment angle and position of the ramp. The sensor provides feedback to a controller that can adjust the ramp deployment parameters in real-time. This allows the system to compensate for varying operating conditions such as road crown, vehicle kneeling capability, and deployment surface, maintaining a consistent and safe ramp slope across different scenarios.
Solution Approach 2:
The ramp system transitions from a static, fixed-slope design to a dynamic system that can adjust its deployment characteristics. The actuator and control system are designed to modify the ramp angle and deployment speed based on real-time conditions, enabling the ramp to adapt to road crown, kneeling capability variations, and different alighting surfaces while maintaining reliability and safety.
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 enhances the accessibility and safety of wheelchair-bound passengers by ensuring a gradual ramp slope and providing an alert for potentially difficult deployment angles, addressing the challenges of torque, manual operation, and varying deployment conditions.
Implementation Method 1
A sensor fitting maintains a fixed orientation relative to a horizontal plane. A sensor is mounted to the sensor fitting such that the sensor senses the target when the ramp portion is in a predetermined position.
Data Source
AI summary
A ramp assembly for providing a transition surface between a vehicle floor and an alighting surface is disclosed. The ramp assembly includes a ramp portion that is rotatable between a stowed position and a deployed position. A target operably associated with the ramp portion so that the target reciprocates along a predetermined path when the ramp portion reciprocates between the stowed position and the deployed position. A sensor fitting maintains a fixed orientation relative to a horizontal plane. A sensor is mounted to the sensor fitting such that the sensor senses the target when the ramp portion is in a predetermined position.