School Bus Emergency Exit Ramp With Automatic Suspension Lowering
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Solution Overview
Problem
Multi-passenger vehicles, such as school buses, pose challenges for emergency egress due to elevated emergency exit doors, which can be difficult for small children and disabled individuals to access safely.
Innovation Solution
An extendable ramp system that automatically deploys from the emergency exit door, lowering the exit opening closer to the ground and adjusting to a more accessible angle, allowing easier exit from the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the emergency exit door is positioned high on the vehicle body, then the structural integrity and safety of the vehicle is improved, but the ease of emergency egress for small children and disabled individuals deteriorates
Solution Approach 1:
A deployable ramp is introduced as an intermediary element between the high emergency exit door and the ground. The ramp bridges the height gap, allowing passengers to safely descend without directly jumping from elevation. The ramp is stored within a housing at normal conditions and automatically deploys when the emergency exit door is opened, providing a continuous surface from the door threshold to the ground level.
2Ease of operation
If a ramp is added to enable ground-level access, then the ease of emergency egress is improved, but the device complexity increases
Solution Approach 1:
The ramp mechanism is merged with the emergency exit door system. The ramp housing is integrated into the door assembly, and the ramp deployment is triggered automatically by the door opening action. This combining of functions reduces the need for separate control systems and minimizes the number of independent components, thereby reducing overall system complexity despite adding the ramp functionality.
Solution Approach 2:
The system is designed to be self-activating: when the emergency exit door is opened, the ramp automatically deploys from its housing without requiring manual intervention. The mechanical connection between the door and ramp mechanism ensures that door opening motion directly triggers ramp deployment, eliminating the need for separate actuators, sensors, or control circuits.
3Ease of operation
If the ramp is extended to the ground, then the ease of descent is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The ramp is designed as a dynamic structure that adjusts its position and angle based on the vehicle's suspension state. When the suspension lowers the vehicle body during emergency egress, the ramp naturally aligns with both the door threshold and the ground. This dynamic adaptation eliminates the need for precise fixed-angle manufacturing, as the ramp's geometry is adjusted in real-time by the suspension system.
Data Source
AI summary
An emergency egress system for a multi-passenger vehicle such as a school bus (372) includes an emergency exit opening (380) that is normally closed by an emergency exit door (382). Opening the emergency exit door of the bus causes the door to open by rotating about at least one horizontal hinge (384). As the door moves outwardly and then downward a ramp (394) moves outwardly from a retracted position toward an extended position. Opening the emergency exit door also causes the suspension of the bus to be automatically lowered to place the emergency exit opening (16) closer to the ground (166).