Elevator Brake Rescue Control for Safety Switch Failures
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Solution Overview
Problem
Existing elevator systems fail to prevent passengers from being trapped due to safety switch failures, despite improved safety measures, necessitating a timely rescue mechanism.
Innovation Solution
An elevator safety control device with an interface unit and safety controller that determines abnormal events by analyzing status signals from safety switches and non-safety function units, enabling the car to travel by gravity and stop at the nearest landing door through controlled brake operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety switches and non-safety function units are improved to high safety performance, then safety performance of the elevator system is improved, but passengers may still be trapped when safety switches fail
Solution Approach 1:
The system performs preliminary actions by continuously monitoring the operational status of safety switches and non-safety function units before failures occur. When anomalies are detected, the system proactively executes rescue modes to prevent passenger entrapment, rather than reacting after entrapment occurs. This includes determining abnormal events in advance and preparing the elevator car to travel to the nearest landing door.
Solution Approach 2:
The system provides beforehand cushioning by establishing multiple layers of protection: primary safety switches, secondary safety switches with individual status determination capability, and non-safety function units with monitoring. This multi-layered approach ensures that if one safety mechanism fails, other mechanisms can still prevent or mitigate passenger entrapment.
2Reliability
If the elevator car stops at a landing door when safety switches are triggered, then passenger safety is protected, but passengers are left trapped and waiting for rescue
Solution Approach 1:
The system determines the possibility of the elevator car stopping at the nearest landing door before actual entrapment occurs. By assessing the status of safety switches and calculating the nearest landing door in advance, the system prepares the rescue operation, reducing the time needed when actual rescue becomes necessary.
Solution Approach 2:
The system dynamically adjusts the elevator car's operation based on real-time status signals from safety switches and non-safety function units. When abnormalities are detected, the system transitions from normal operation to rescue mode, dynamically controlling the holding brake device to enable the car to travel by gravity to the nearest landing door, thereby reducing rescue time.
3Ease of operation
If the elevator car is controlled to travel by gravity and stop at the nearest landing door, then passenger evacuation is enabled, but the normal operation is disrupted
Solution Approach 1:
The system determines abnormal events and assesses the possibility of safe stopping at the nearest landing door before executing the gravity travel sequence. By performing these determinations in advance, the system minimizes the disruption to normal operation and ensures that gravity travel is only initiated when necessary and safe.
Solution Approach 2:
The system continuously receives status signals from safety switches and non-safety function units, providing feedback to the control device. This feedback mechanism allows the system to monitor the elevator car's position, the status of safety switches, and the operational conditions, enabling timely decisions to initiate or terminate gravity travel mode while minimizing disruption to normal operation.
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
Enables safe and timely evacuation of passengers by ensuring the elevator car stops at the nearest landing door during safety switch failures, reducing the risk of entrapment.
Implementation Method 1
in the rescue mode, the car is caused to travel by gravity and stop at the landing door of the nearest floor by controlling a state of a holding brake device
Data Source
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AI summary
The present disclosure relates to elevator technology and, in particular, to an elevator safety control device, a method for elevator safety control, an elevator system comprising the device, a non-transitory computer-readable storage medium for implementing the method, and a computer program product. In accordance with an aspect of the present disclosure, an elevator safety control device comprises: an interface unit that receives a first status signal of a first safety switch, a second status signal of a second safety switch, and a third status signal of a non-safety function unit of an elevator, the second safety switch comprising a plurality of landing door switches whose status can be determined individually; a safety controller that performs the following operations: determining an occurrence of an abnormal event based on the first status signal, the second status signal and the third status signal; determining, after determining the occurrence of the abnormal event, a possibility of a target landing door based on the second status signal; and executing a rescue mode after determining an existence of the possibility, wherein in the rescue mode, the car is caused to travel by gravity and stop at the target landing door by controlling a state of a holding brake device.