Car-Mounted Governor Encoder Layout for Elevator Position Sensing
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Solution Overview
Problem
Existing elevator systems lack accurate and cost-effective methods for determining the position and speed of elevator cars, particularly for critical safety functions requiring high precision.
Innovation Solution
Incorporating a car-mounted governor (CMG) with encoders on idler and traction pulleys to generate signals for position and speed determination, coupled with a processing board for redundant computation and safety relay operations, and utilizing discrete sensors for calibration and re-calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete sensors are deployed in the hoistway for position detection, then position detection capability is provided, but material costs and installation complexity increase
Solution Approach 1:
The patent extracts the position detection function from the traditional discrete sensors deployed in the hoistway and relocates it to the car-mounted governor. The encoder is mounted on the governor pulley, which rotates with the rope, allowing position detection without requiring separate sensors in the hoistway. This reduces material costs and installation complexity while maintaining measurement precision.
2Measurement precision
If encoders are mounted on governor pulleys, then accurate position and speed information is obtained, but device complexity increases
Solution Approach 1:
The car-mounted governor is enhanced with encoder functionality, transforming it from a single-function safety device into a multi-functional component that provides both safety governor functions and precise position/speed measurement. The encoder mounted on the governor pulley leverages the existing rotational motion of the rope to generate position and speed signals, eliminating the need for separate measurement systems.
Solution Approach 2:
The patent merges the position detection system with the governor system by integrating the encoder directly onto the governor pulley. This combination allows the governor mechanism to simultaneously perform its safety function and provide accurate position and speed measurement, reducing overall system complexity despite the added measurement capability.
3Reliability
If multiple encoders are deployed on idler and traction pulleys, then redundant position determination is achieved for safety, but manufacturing costs increase
Solution Approach 1:
The patent replaces traditional mechanical position detection methods with encoder-based electromagnetic sensing. The encoders mounted on the governor pulley provide electronic signals for position and speed determination, offering higher reliability and redundancy without the mechanical complexity and cost of multiple discrete sensor systems.
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
Provides accurate and low-cost elevator car position and speed information, ensuring SIL 3 compliance with enhanced overspeed detection and safety actuation, reducing material and installation costs.
Implementation Method 1
The at least one encoder is mountable on one of the idler and traction pulleys and is configured to generate a signal reflective of rotation of the one of the idler and traction pulleys
Data Source
AI summary
An elevator system in which an elevator car travels in a hoistway is provided. The elevator system includes an anchor, a tensioning mass, a car-mounted governor (CMG) affixable to the elevator car, a rope and a processing board. The CMG includes idler and traction pulleys and at least one encoder mountable on one of the idler and traction pulleys and configured to generate a signal reflective of rotation of the one of the idler and traction pulleys on which the at least one encoder is mounted. The rope is extendible from the anchor, around the idler and traction pulleys and to the tensioning mass to cause idler and traction pulley rotation when the elevator car travels in the hoistway. The processing board is receptive of the signal and is configured to determine at least a position of the elevator car in the hoistway from the signal.