Elevator Door Width Detection for Accurate Passenger Entrapment Alarms
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Solution Overview
Problem
Current elevators lack the ability to accurately detect the opening and closing state of the elevator-car door, particularly the opening width, which affects the accuracy of detecting whether a passenger is trapped.
Innovation Solution
An operating system for elevators that includes a passenger detection device, an elevator-car door state detection device with multiple electromagnetic switches, and a processing device to determine the opening width and state of the elevator-car door, outputting an alarm signal when a passenger is present and the door is insufficiently open during a failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple door sensors are used to detect door closed state, then device complexity is reduced, but measurement precision of door opening width is insufficient
Solution Approach 1:
The door detection system is segmented into multiple electromagnetic switches positioned at different locations (first switch at 10-20cm from closed position, second switch at 30-40cm from closed position). This segmentation allows the system to detect different door opening states independently, enabling precise measurement of door opening width while maintaining relatively simple device structure.
Solution Approach 2:
The patent introduces a third electromagnetic switch installed on the elevator-car door that moves together with the door as an intermediary element. This moving switch interacts with the stationary first and second switches to provide information about door opening state, enabling precise width detection without requiring complex direct measurement mechanisms.
2Measurement precision
If multiple electromagnetic switches are installed to detect door opening width, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The multiple electromagnetic switches serve multiple functions: the first switch detects when the door opening reaches 10-20cm, the second switch detects when the door opening reaches 30-40cm, and together they enable calculation of door opening width. This multi-functionality allows precise measurement without requiring each switch to be a complex independent measurement device.
Solution Approach 2:
The patent replaces complex mechanical measurement mechanisms with electromagnetic switches that detect door opening state through magnetic field interaction. This substitution maintains measurement precision while significantly reducing device complexity compared to mechanical measurement systems.
3Ease of operation
If door closing state is not accurately detected, then passenger trapped detection accuracy is reduced, but system simplicity is maintained
Solution Approach 1:
The processing device receives feedback signals from multiple electromagnetic switches about door opening width and combines this with passenger presence detection to determine whether a passenger is trapped. This feedback mechanism ensures accurate passenger trapped detection while maintaining system simplicity through logical processing of sensor inputs.
Solution Approach 2:
The system performs preliminary detection of door opening width using electromagnetic switches before making the final determination of passenger entrapment. This preliminary action ensures accurate assessment of door state, allowing the system to reliably determine whether a passenger is trapped while keeping the overall system simple and efficient.
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
Enhances the accuracy of detecting passenger entrapment by accurately determining the opening and closing states of the elevator-car door, ensuring timely alarm signals are generated when a passenger is trapped.
Implementation Method 1
a first electromagnetic switch, installed on an elevator-car door frame, with a predetermined distance from a closed position of the elevator-car door; a second electromagnetic switch, installed on the elevator-car door frame, adjacent to the first electromagnetic switch
Data Source
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Figure 3
AI summary
An operating system for an elevator and an elevator operating method. The operating system comprises: a passenger detection apparatus, configured to detect whether there is a passenger in an elevator car and to send out a signal indicative of whether there is a passenger; a car door state detection apparatus, configured to detect whether a car door has an opening degree smaller than or equal to a preset opening degree and to send out a signal indicative of whether the car door has an opening degree smaller than or equal to the preset opening degree; and a processing apparatus, communicatively coupled to the passenger detection apparatus and the car door state detection apparatus, and configured to: receive the signal indicative of whether the car door has an opening degree smaller than or equal to the preset opening degree; and when an elevator has a fault, and when the processing apparatus receives from the passenger detection apparatus a signal indicating that there is a passenger in the elevator car and receives from the car door state detection apparatus a signal indicating that the car door has an opening degree smaller than or equal to the preset opening degree, send out an alarm signal.