Elevator Speed Reducing Switch Control System
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Solution Overview
Problem
Modern elevator systems require more robust and reliable safety systems to manage increasing speeds, particularly at rates above 200 FPM, necessitating a speed reducing switch that can manually reset and operate before the speed governor's tripping point to prevent over-speed conditions.
Innovation Solution
An electronic speed reducing switch integrated into the elevator system's control system, which senses the elevator car's speed and activates a software tripping point before the speed governor's electrical tripping point, arresting motion and setting a slow down latch, with a manual reset module to ensure compliance with safety codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical speed reducing switch is used to reduce elevator speed in over-speed conditions, then safety is improved, but device complexity increases due to additional hardware requirements
Solution Approach 1:
The patent replaces the traditional mechanical speed reducing switch with an electronic control system that uses software to detect over-speed conditions and activate the brake. The controller monitors elevator speed through existing sensors and executes braking commands through electronic control signals, eliminating the need for separate mechanical speed reducing switches while maintaining safety functionality.
Solution Approach 2:
The controller is designed to perform multiple functions: it controls normal elevator operation, monitors speed through existing sensors, detects over-speed conditions, and activates the brake system. By making the controller multi-functional, the patent eliminates the need for dedicated speed reducing switches and other separate safety devices, thereby reducing overall system complexity while maintaining safety.
2Reliability
If a speed reducing switch with manual reset is implemented to comply with safety codes, then reliability is improved, but ease of operation deteriorates due to manual reset requirement
Solution Approach 1:
The system automatically detects over-speed conditions and activates the brake without requiring manual intervention. The controller continuously monitors speed parameters and autonomously executes braking commands when thresholds are exceeded, making the system self-regulating and eliminating the need for manual reset operations while maintaining code compliance.
3Reliability
If the speed reducing switch tripping point is set below the speed governor tripping point, then safety margin is improved, but speed control precision worsens due to earlier intervention requirement
Solution Approach 1:
The patent implements dynamic speed threshold monitoring where the controller continuously adjusts and monitors speed parameters in real-time. The system can activate the brake at variable speed thresholds based on actual operating conditions, allowing flexible control that maintains safety margins while adapting to different operational scenarios, thereby achieving both safety and precision requirements.
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 electronic speed reducing switch effectively reduces elevator car speed in over-speed situations, enhancing safety and compliance with code requirements by providing a reliable and manual reset mechanism without the need for additional hardware, leveraging existing elevator system components and modifying the controller's software.
Implementation Method 1
as the elevator car travels up and down the elevator shaft, flyweights provided on the governor pulley move outwardly due to the centrifugal force imparted thereon by the rotating governor pulley
Data Source
AI summary
A system and method for controlling speed of an elevator car in an elevator system is disclosed. The elevator car may have a speed governor adapted to trip when an electrical tripping point of the speed governor is reached. The elevator system may also have a control system for controlling operation of the elevator car, the control system providing a speed reducing switch adapted to trip when a software tripping point of the speed reducing switch is reached, the software tripping point being reached before the electrical tripping point of the speed governor.