Elevator Final Limit Control Using Parametric Position Data
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Solution Overview
Problem
Existing elevator safety systems face challenges in accurately adjusting the position of final limit switches due to mounting tolerances and dimensions, leading to potential collisions with safety buffers before the switches are triggered, necessitating difficult and time-consuming physical adjustments.
Innovation Solution
The system replaces physical markers in the hoistway with position data stored in a safety controller, using a scale and Hall sensors to determine the absolute position of the elevator car within the final movement zone, allowing for adjustable emergency stops without physical repositioning of hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical markers and mechanical ramps are used to define final limit positions, then the safety system can trigger emergency stops, but mounting tolerances and dimensional variations cause the car to hit the buffer before the limit switch is triggered
Solution Approach 1:
The patent replaces mechanical limit switches and physical markers with an electronic monitoring system using optical sensors and a computer. The system uses optical markers positioned at predetermined locations and detects car position through optical sensors, eliminating mechanical mounting tolerance issues. The computer processes sensor signals to determine when the car reaches final limit positions, providing precise control without physical adjustment needs.
Solution Approach 2:
The patent changes the final limit position parameters by adjusting the predetermined distance values in the computer's memory rather than physically repositioning markers or switches. The system stores multiple predetermined distance values corresponding to different final limit positions, allowing software-based parameter adjustment to accommodate buffer position variations and achieve accurate emergency stop triggering.
2Measurement precision
If the position of final limit switches is adjusted physically to account for mounting tolerances, then accurate emergency stops can be achieved, but the adjustment process is difficult and time-consuming
Solution Approach 1:
The patent replaces mechanical limit switches requiring physical adjustment with an electronic system where the computer calculates and determines final limit positions based on sensor inputs and predetermined distance values. This substitution eliminates the need for time-consuming physical repositioning of markers and switches, allowing rapid configuration through software parameter setting.
Solution Approach 2:
The system allows dynamic adjustment of final limit positions by modifying predetermined distance values in the computer's memory without physical hardware changes. The computer can adapt the monitoring parameters based on actual buffer positions and operational requirements, enabling flexible reconfiguration without mechanical adjustment work.
3Reliability
If mechanical ramps are mounted in the shaft to trigger final limit switches, then emergency stops can be activated, but the installation is difficult and position adjustment is restricted
Solution Approach 1:
The patent replaces mechanical ramps with optical markers and electronic sensors. The optical markers can be positioned at predetermined locations without complex mechanical mounting structures, and the sensors detect marker positions electronically. This substitution greatly simplifies installation and allows easier repositioning if adjustment is needed, while maintaining reliable emergency stop functionality.
4Productivity
If the car is allowed to move beyond the final limit marker position, then the final movement zone can be utilized, but the car may collide with the safety buffer if the limit is not precisely adjusted
Solution Approach 1:
The patent implements a feedback system where optical sensors continuously monitor the car's position relative to optical markers, and the computer processes this information to determine when the car approaches final limit positions. The system provides real-time feedback on car location, allowing precise control of the final movement zone and automatic triggering of emergency stops before buffer collision occurs, eliminating the need for conservative position limits.
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
Enables precise adjustment of final movement zones through software, reducing the need for physical repositioning of hardware, thus avoiding collisions and lowering production costs while maintaining safety integrity.
Implementation Method 1
using a scale and Hall sensors to determine the absolute position of the elevator car within the final movement zone
Data Source
Figure 1
AI summary
The invention is about an elevator safety system, comprising an electronic safety controller (20) running a software comprising a monitoring mode for monitoring 5 the position of an elevator car (3) within a hoistway (4). The system comprises a position measurement device (2; 21) for measuring said elevator car position. Further, there are limit position identification markers (1C; 1E) being installed in the hoistway (4) for defining a starting point of a final movement zone in which the car is still allowed to run in direction to the outermost ends of the hoistway. However, as soon as the end of the final limit zone is reached by the car, an emergency stop is triggered. According to the invention, the position data for the final limit zone are laid down in a memory of the safety controller as parametrized data for being able to adjust them if so needed. Therewith, it can be avoided that the hardware components in the shaft have to be replaced.