Elevator Speed Control via Traction Sheave Monitoring
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Solution Overview
Problem
Existing elevator speed monitoring systems require complex and expensive hardware, which is costly to maintain and does not effectively prevent overspeeding or ensure safe deceleration of elevator cars.
Innovation Solution
A detection system that records and evaluates the movement of the traction sheave and counterweight, initiating deceleration if the elevator car overspeeds, and uses a simple safety circuit to activate a brake if the car does not reach a standstill position within predetermined specifications, thereby preventing overspeeding and ensuring safe stoppage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex hardware monitoring systems are used to track cable drum and motor shaft revolutions, then speed monitoring capability is improved, but device complexity and maintenance cost increase
Solution Approach 1:
The patent extracts the speed monitoring function from complex mechanical sensing systems and relocates it to a computer-based evaluation system that processes signals from a simple measuring system, eliminating the need for complex electrical monitoring of motor shaft and drum shaft revolutions
Solution Approach 2:
The patent replaces complex electrical monitoring hardware with a computer-based system that evaluates signals from a simplified measuring system, using software logic instead of complex hardware circuits to achieve speed monitoring and control
2Reliability
If continuous monitoring and multiple check points are implemented, then safety reliability is improved, but response time and system complexity increase
Solution Approach 1:
The patent establishes predetermined speed specifications and deceleration criteria in advance, allowing the computer to immediately compare actual speed against these pre-set thresholds and initiate deceleration without complex real-time calculations, thus maintaining fast response while ensuring safety
Solution Approach 2:
The patent implements a feedback mechanism where the computer continuously monitors speed via the measuring system and compares it against predetermined specifications, automatically initiating deceleration when deviations are detected, and verifying that deceleration progresses according to predetermined criteria
Data Source
Figure 1a
Figure 1b
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AI summary
The method involves detecting and evaluating movement of an elevator car and counterbalance driving traction sheave. A deceleration of the car is initiated with an impermissible deviation of the speed of the car from a preset speed. The car is monitored to find whether it quits its standstill position, and a brake is activated to ascertain the car, when the car has quitted its standstill position. An independent claim is also included for a detection system for monitoring speed of an elevator car, comprising a measuring system.