Landing Door Sensor Backup Power for Elevator Safety Recovery
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Solution Overview
Problem
Elevator systems cannot monitor landing doors during power outages, leading to unnecessary activation of safety modes and manual resets when power is restored, as they assume the hoistway was accessed, even if it wasn't.
Innovation Solution
An elevator safety device with a power source independent of the elevator system's power supply, which powers a landing door sensor and records its state, allowing continuous monitoring and automatic reporting to the elevator controller upon power restoration, enabling immediate resumption of normal operation if no access occurred.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the elevator system uses the main power supply to monitor landing doors, then the monitoring system is simple and integrated, but the monitoring stops during power outages leading to unnecessary safety mode activations
Solution Approach 1:
The power supply system is segmented into two independent parts: the main power supply for general elevator operations and an independent backup power source (battery) specifically for landing door monitoring. This segmentation allows the monitoring function to operate independently during power outages, resolving the contradiction between reliability and complexity by isolating the critical monitoring function from the main power system failures.
Solution Approach 2:
The battery power source is pre-charged during normal operation when the main power supply is available. This preliminary energy storage ensures that the landing door sensor can continue monitoring immediately when the main power fails, without requiring complex real-time power switching or external power sources during outages.
2Reliability
If the elevator system assumes hoistway access during power interruptions, then safety is maintained, but normal operation requires manual reset causing inconvenience
Solution Approach 1:
The system implements feedback through the memory device that records actual landing door states during power outages. After power restoration, this recorded information is read to determine whether hoistway access actually occurred, providing accurate feedback that replaces the previous assumption-based safety approach. This enables automatic resumption of normal operation when no access occurred, improving ease of operation while maintaining safety through accurate monitoring.
Solution Approach 2:
The memory device pre-records the landing door state information during the power outage period. This preliminary recording of actual conditions allows the system to make informed decisions after power restoration, avoiding unnecessary manual resets and safety mode activations when the recorded data shows no hoistway access occurred.
3Reliability
If manual reset is required after power restoration, then false safety mode activations are prevented, but operational efficiency decreases due to unnecessary interventions
Solution Approach 1:
The memory device provides accurate feedback about actual landing door states during power outages, replacing the need for conservative manual reset assumptions. The system reads this recorded information after power restoration to determine whether false safety mode activations should occur, automatically distinguishing between actual hoistway access and normal power interruptions, thereby maintaining reliability while eliminating unnecessary manual interventions that reduce productivity.
Solution Approach 2:
The system performs self-diagnosis and self-decision-making after power restoration by automatically reading the recorded landing door states from memory and determining whether normal operation can resume. This self-service capability eliminates the need for manual operator intervention in cases where no hoistway access occurred, improving operational efficiency while maintaining safety through automated accurate assessment.
Data Source
AI summary
An elevator safety device 16 for monitoring a landing door 10 of an elevator system 2. The elevator system 2 includes a landing door sensor 14 arranged to detect a state of the landing door 10. The elevator safety device 16 includes a power source 20 arranged to power the landing door sensor 14 independently of a power supply 19 of the elevator system 2 and a memory 22 arranged to record a state of the landing door 10 detected by the landing door sensor 14 when the landing door sensor 14 is powered by the power source 20.