Car-Mounted Governor Encoder for Elevator Position and Overspeed Detection
Find Innovative SolutionsGenerate Solutions
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 SIL 3 compliance.
Innovation Solution
Incorporating a car-mounted governor (CMG) with encoders on idler and traction pulleys, coupled with a processing board for redundant circuitry, to provide accurate speed and position information, and integrating discrete sensors for calibration and re-calibration, ensuring SIL 3 safety compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional position detection methods are used in elevator systems, then the system structure is simple, but the measurement precision and reliability for safety functions are insufficient
Solution Approach 1:
The patent replaces traditional mechanical position detection systems with an encoder-based measurement system. The encoder mounted on the CMG pulley converts mechanical rotation into electrical signals, providing precise digital position and speed data without complex mechanical linkages or multiple discrete sensors throughout the hoistway.
Solution Approach 2:
The encoder system serves multiple functions simultaneously: it provides both position detection and speed measurement for the elevator car, and enables multiple safety functions including overspeed detection, loss of traction detection, and car position monitoring. This multi-functionality reduces the need for separate dedicated sensors for each safety function.
2Measurement precision
If multiple discrete sensors are deployed for position detection, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
The patent combines multiple position detection and speed measurement functions into a single encoder unit mounted on the CMG pulley. This consolidation replaces what would traditionally require multiple discrete sensors distributed throughout the hoistway, reducing component quantity while maintaining measurement precision through the encoder's direct coupling with the rope motion.
3Reliability
If redundant safety systems are implemented for SIL 3 compliance, then the reliability improves, but the device complexity and material requirements increase
Solution Approach 1:
The encoder provides continuous feedback on the CMG pulley rotation position and speed, enabling the control system to monitor elevator car position and speed in real-time. This feedback mechanism allows for accurate detection of overspeed conditions, loss of traction, and abnormal car positions, providing the reliable data needed for SIL 3 safety compliance without requiring multiple redundant physical safety devices.
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
The CMG encoder system offers accurate and reliable elevator car position and speed detection, enhancing safety functions like overspeed detection and loss-of-traction monitoring while reducing costs and material requirements.
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
Figure 1
Figure 2~4
Figure 5
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.