Low Profile Gap Mitigation Device for Transit Vehicles
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Solution Overview
Problem
Current gap mitigation devices for transit vehicles require high manual effort for stowage, lack remote cutout operation, and have a high profile design, failing to accommodate varying gap dimensions and ensuring safe wheelchair access as per ADA regulations.
Innovation Solution
A powered gap mitigation device with a clutch linkage driven by a motor, allowing the gap mitigation plate to move between stowed and deployed positions, featuring a low-profile design, remote cutout mechanism, and low manual stowage force, using a push-pull cable and solenoid-release lock for secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a lead screw and nut arrangement is used for bridgeplate actuation, then the bridgeplate can be actuated with a motor drive, but the manual stowage requires relatively high force to backdrive the screw and nut arrangement
Solution Approach 1:
The patent extracts the high-force backdriving requirement from the lead screw mechanism by introducing a separate manual stowage actuation path. The manual actuator directly drives the bridgeplate without engaging the lead screw, eliminating the need to overcome screw friction during manual operation.
Solution Approach 2:
The patent introduces a clutch mechanism as an intermediary between the motor/lead screw system and the manual actuator. This clutch selectively engages or disengages the lead screw from the bridgeplate drive, allowing manual force to be applied directly to the bridgeplate when the clutch is disengaged, rather than through the high-friction lead screw.
2Device complexity
If a fixed outboard deployment length is used for the GMD, then the device structure is simplified, but it does not entirely fill the gap in case of gaps of different dimensions from platform to platform or from door to door in the case of curved platforms
Solution Approach 1:
The patent transforms the fixed-length bridgeplate into a variable-length configuration through the addition of an extendable section. This extendable section can be actuated to increase the deployment length when larger gaps are detected, allowing the same basic structure to adapt to different gap dimensions without requiring completely different designs.
Solution Approach 2:
The system performs preliminary gap measurement and evaluation before deployment. Based on the measured gap dimensions, the control system pre-determines the required deployment length and actuates the extendable section accordingly, ensuring the bridgeplate is properly sized before it needs to be deployed.
3Adaptability or versatility
If the GMD deployment length is extended to accommodate varying gap dimensions, then gap filling capability is improved, but the device height profile increases
Solution Approach 1:
The extendable section is designed to nest within the main bridgeplate body when not in use. This nesting arrangement allows the variable-length capability to be achieved without permanently increasing the device's height profile, as the extended portion is contained within the existing structure boundaries.
Solution Approach 2:
Instead of increasing the vertical height profile to accommodate varying gap lengths, the patent extends the bridgeplate horizontally in the longitudinal direction of the vehicle. This dimensional shift allows the device to adapt to different gap sizes without compromising the low-profile requirement in the vertical dimension.
4Use of energy by moving object
If manual stowage actuation is used for the GMD, then the device can be stowed without power, but the lever for manual stowage cannot be remotely actuated
Solution Approach 1:
The patent introduces a cable-operated lever mechanism as an intermediary between the operator and the manual stowage actuator. This cable linkage transmits the operator's input force from a remote location to the stowage mechanism, enabling remote actuation while maintaining the passive, powerless stowage capability.
Solution Approach 2:
The patent replaces direct mechanical connection with a cable-based mechanical transmission system. This substitution allows the manual stowage lever to be positioned remotely from the actual stowage mechanism, providing operational flexibility and ease of use while maintaining the simple mechanical, power-free operation.
Data Source
AI summary
A powered gap mitigation device for transit vehicles allows a gap mitigation plate to move outboard from its stowed position, be locked in the deployed position, move inboard from a deployed position to a stowed position, be locked in the stowed position, and be manually stowed and cut-out in case of malfunction.