Elevator Safety System Acceleration Threshold Braking
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Solution Overview
Problem
Elevator safety systems face challenges in determining when to initiate emergency braking, particularly in cases of overspeed or abnormal acceleration, which can occur due to issues like rope breakage, and existing systems may not respond quickly enough to ensure passenger safety.
Innovation Solution
An elevator safety system that includes a position reference system to determine the current position of the elevator car and a controller to calculate acceleration, comparing it to a predetermined threshold to activate brakes when excessive acceleration is detected, allowing for timely and safe stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the elevator safety system uses speed monitoring with predefined overspeed threshold, then the system can detect abnormal speed, but the response time is insufficient to ensure passenger safety in emergency situations
Solution Approach 1:
The system pre-calculates expected acceleration profiles and thresholds before emergency situations occur. By establishing predetermined acceleration thresholds and comparing real-time acceleration against these pre-established criteria, the system enables faster detection of abnormal acceleration patterns without requiring complex real-time calculations during emergencies, thus reducing response time while maintaining safety reliability
Solution Approach 2:
The patent replaces traditional speed-based mechanical monitoring with an acceleration-based detection system. By using acceleration sensors and comparing measured acceleration against predetermined thresholds, the system achieves more rapid detection of emergency conditions (such as rope breakage) compared to traditional speed monitoring, thereby improving safety response effectiveness while reducing loss of time
2Reliability
If the controller continuously monitors speed to detect overspeed conditions, then the system can identify abnormal speed, but the system complexity increases
Solution Approach 1:
The patent substitutes continuous speed monitoring with acceleration monitoring. By using acceleration sensors to directly measure acceleration and comparing it against predetermined thresholds, the system achieves reliable detection of abnormal motion conditions with simpler control logic, reducing device complexity while maintaining or improving monitoring accuracy
Solution Approach 2:
The system changes the monitored parameter from speed to acceleration. This parameter change simplifies the monitoring system because acceleration can be directly measured by sensors and compared against fixed thresholds, eliminating the need for complex continuous speed profile analysis and reducing overall system complexity while maintaining reliability
Data Source
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AI summary
According to a first aspect of this disclosure there is provided an elevator safety system for an elevator system comprising: a position reference system configured for determining a current position of an elevator car within the elevator system; at least one brake configured to bring the elevator car to a safe stop; a controller configured to activate the at least one brake; wherein the controller is configured to: receive data from the position reference system; calculate a current acceleration from the current position of the elevator car; compare the current acceleration to a predetermined acceleration threshold; and activate the at least one brake when the current acceleration exceeds the predetermined acceleration threshold.