Elevator Car Distance Sensing for Shared-Shaft Collision Protection
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Solution Overview
Problem
Existing elevator systems with multiple cars in a shared shaft face challenges in preventing collisions with other cars or structures, posing a risk to passenger safety and complicating maintenance operations.
Innovation Solution
An elevator safety system with a distance measurement device and safety unit on each car, capable of determining distances to static or dynamic targets, and initiating stops based on safety thresholds, speed, and direction, integrated with a control unit to manage car movements and safety devices at turning stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple elevator cars are allowed to operate in the same shaft, then productivity is improved, but the risk of collision between elevator cars increases
Solution Approach 1:
The system performs preliminary distance measurement and safety assessment before allowing elevator car movement. The distance measurement device continuously monitors the distance to other elevator cars or obstacles, and the safety unit pre-calculates safe operating parameters, initiating stopping actions before collision risk materializes.
Solution Approach 2:
The system establishes a closed-loop feedback mechanism where the distance measurement device continuously reports the distance between elevator cars to the safety unit, which adjusts the operational status in real-time. This feedback loop enables dynamic safety control, allowing multiple cars to operate safely by continuously adapting to changing distances and speeds.
2Reliability
If distance measurement and safety monitoring are implemented, then collision prevention is improved, but device complexity increases
Solution Approach 1:
The safety unit performs multiple functions: it processes distance measurements, determines safe operating parameters, controls the mover, and manages stopping actions. This multi-functionality reduces the need for separate dedicated components for each safety function, thereby limiting the increase in overall system complexity while maintaining comprehensive safety coverage.
Solution Approach 2:
The safety unit autonomously processes safety assessments and initiates stopping actions without requiring external intervention. The system self-regulates by continuously monitoring distance, evaluating safety conditions, and automatically executing protective measures, which simplifies the control architecture compared to systems requiring multiple external safety devices and manual oversight.
3Ease of operation
If the elevator car can move freely in the shaft, then ease of operation is improved, but the risk of collision with obstacles or other cars increases
Solution Approach 1:
The safety unit applies preliminary anti-action by pre-calculating safe operating parameters and initiating stopping actions before collision can occur. The system continuously assesses the risk of collision with obstacles or other elevator cars and takes preventive measures, such as limiting speed or initiating braking, to counteract the harmful effect before it materializes.
Solution Approach 2:
The system dynamically adjusts the elevator car's operating parameters based on real-time distance measurements and safety assessments. The mover's speed, direction, and acceleration are continuously modified according to the current operational context, allowing the elevator to move freely when safe while automatically restricting movement when collision risk is detected.
Data Source
AI summary
An elevator safety system includes an elevator car safety unit arranged on or at least in mechanical connection, preferably in fixed manner, with an elevator car; at least one distance measurement target; and a distance measurement device mounted on the elevator car for determining a distance between the distance measurement target and the distance measurement device. The elevator car safety unit is arranged in connection with the distance measurement device and is configured to generate an output signal based on the determined distance.