Park Brake Pressure Loss Detection for Lift Platform Vehicles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing systems for motor vehicle wheelchair lifts can inadvertently shut off compressed air supply to the park brake, leading to potential unintended application of the brake while the vehicle is in motion due to leaks or electrical system failures, which may result in the brake being applied while driving, posing a safety risk.
Innovation Solution
A pressure-sensitive device is integrated into the air line leading to the park brake's SAAR, connected to the vehicle's electrical system, to alert the driver of impending pressure loss, utilizing existing warning devices and systems to ensure timely stopping before the brake is applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the solenoid-operated interlock valve shuts off compressed air supply to the park brake when the lift is out of stow, then the vehicle is rendered immovable and compliant with wheelchair lift regulations, but compressed air may become trapped in the air line when the vehicle is driven, leading to potential unintended park brake application
Solution Approach 1:
The pressure-sensitive device detects pressure loss in the air line before it causes unintended park brake application, allowing the driver to take preliminary action (stop the vehicle) before the harmful effect occurs. The system performs the detection function in advance, enabling preventive measures.
Solution Approach 2:
The pressure-sensitive device continuously monitors air pressure in the line to the SAAR and provides feedback to the driver through an alert signal when pressure drops below a threshold. This feedback mechanism allows the driver to respond to the developing condition and prevent unintended brake application.
2Ease of operation
If the supply valve opens to pass compressed air from supply port to delivery port when the lift is in stow, then the park brake knob can apply and release the park brake, but leakage in the air line cannot be compensated when the supply valve is closed, leading to pressure loss and potential park brake application
Solution Approach 1:
The pressure-sensitive device provides continuous monitoring and feedback on air pressure in the line to the SAAR. When pressure drops due to leakage, the device alerts the driver, enabling timely response to maintain system reliability.
Solution Approach 2:
The pressure-sensitive device acts as an intermediary between the air line pressure system and the driver. It translates pressure changes into actionable information, bridging the gap between the closed-loop air system and human operation.
3Reliability
If a pressure-sensitive device is integrated into the air line to detect pressure loss and alert the driver, then the driver is warned of impending pressure loss, but the system complexity increases with additional components
Solution Approach 1:
The pressure-sensitive device serves multiple functions: it monitors air pressure, detects pressure loss, and provides driver alerting. By consolidating these functions into a single component, the system achieves improved reliability without proportionally increasing complexity.
Solution Approach 2:
The pressure-sensitive device automatically monitors and detects pressure conditions without requiring manual intervention. The system self-regulates by providing alerts when pressure drops, reducing the need for additional complex control 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 the driver with sufficient time to safely stop the vehicle and address the issue, preventing unintended park brake application and ensuring compliance with safety regulations.
Implementation Method 1
A pressure-sensitive device is integrated into the air line leading to the park brake's SAAR, connected to the vehicle's electrical system, to alert the driver of impending pressure loss
Implementation Method 2
Application of a park brake occurs when the air supply to the SAAR is shut off, allowing the spring force of the SAAR to be effective to lock the wheels. Pressurized air must be applied to the SAAR in order to release the park brake
Data Source
AI summary
A method for warning a driver of a moving vehicle of potential imminent unintended application of a park brake because of an indication that a motorized lift (12) is out-of-stow. A processor (68) executes an algorithm for issuing an alarm to signal the driver when air pressure in a line (46) to a device (50) that is holding the park brake released has decreased to pressure somewhat greater than that which will cause the park brake to be automatically applied, allowing the driver some measure of time to park the vehicle before the park brake is applied.