Elevator Rope Pulley Encoder for Accurate Hoistway Position Detection
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Solution Overview
Problem
Existing elevator systems face reliability and maintenance issues in accurately determining the position of the elevator car within the hoistway due to the wear-prone nature of mechanical switches and the need for extensive installation and recalibration of permanent magnets, which increases costs and complexity.
Innovation Solution
A rope pulley system with an encoder is used to measure the rotational movement of the hoisting rope, allowing for accurate calculation of the elevator car's position by correlating the rotational data with markers along the hoistway, and a safety bus node connects the encoder to a safety controller for enhanced reliability and self-diagnostic capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If permanent magnets are installed along the hoistway for position detection, then car position can be determined accurately, but installation and maintenance work increases enormously
Solution Approach 1:
Instead of placing sensors along the hoistway wall to detect magnets, the patent inverts the approach by mounting magnets directly on the moving car and placing corresponding sensors at fixed positions in the hoistway. This reduces the total number of components and simplifies installation while maintaining accurate position detection
2Measurement precision
If reed switches and permanent magnets are used for position detection, then landing positions can be identified, but the system requires extensive calibration and adjustment
Solution Approach 1:
The patent implements a system where the controller automatically determines the relationship between magnet positions and hoistway locations during operation. The system self-calibrates by tracking the movement of magnets on the car relative to fixed sensors, eliminating the need for manual calibration and adjustment of landing positions
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
This solution provides a cost-effective, robust, and accurate method for determining the elevator car's position, reducing maintenance needs and ensuring high safety standards with minimal installation time and no requirement for end-to-end shaft length measurement.
Implementation Method 1
the encoder is a magnetic encoder. In this case, the rope pulley comprises a magnetic band or magnetic ring that is mounted on a rotating shelf of the pulley, while a magnetic reader is stationarily mounted
Implementation Method 2
Other alternative solutions for the encoder are any other suitable rotating encoder, such as optical encoder
Data Source
Figure 1
Figure 2
AI summary
The invention is about a rope pulley (2) of an elevator system, which is a free rotating pulley (2) around which a hoisting rope of the elevator system can be guided. Said free pulley is to be mounted to a car sling (1) of an elevator car, wherein the pulley (2) comprises an encoder for measuring the rotation movement of the pulley. The movement data are transmitted to a controller that converts the movement data into position data of the car in the hoistway, while further position data are gathered from identification markers that are installed in the hoistway. At least, the movement data of the rope pulley(s) are calibrated based on the position data from the identification markers. By means of that, the position of the car in the hoistway can be determined accurately and costly.