Elevator Overspeed Governor with Variable Speed Triggering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional overspeed governors for elevators can only be triggered at a single speed level, which is inadequate as elevator car speeds vary, and there is a need for enhanced safety, especially when the car is near hoistway ends where braking distance is limited.
Innovation Solution
An overspeed governor with a permanent magnet rotor and stator that interacts to exert a braking force through a magnetic field, allowing for non-contact activation of the safety gear at multiple speed levels, utilizing a control unit to manage the activation based on elevator car movement and position, and incorporating a tensioning pulley for the safety rope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single speed level threshold is used for overspeed governor activation, then the device structure remains simple, but safety cannot be enhanced when the elevator car is near hoistway ends where braking distance is limited
Solution Approach 1:
The patent applies dynamics by making the overspeed governor's triggering speed threshold variable rather than fixed. The governor can be adjusted to trigger at different speed levels depending on the elevator car's position - specifically, at lower speed levels when the car is near hoistway ends where braking distance is limited, and at higher speed levels when more braking distance is available. This dynamic adjustment optimizes safety based on operating conditions without requiring a completely complex multi-system architecture.
Solution Approach 2:
The patent implements parameter changes by modifying the speed threshold parameter of the overspeed governor based on elevator car position. The system changes the critical speed parameter dynamically - using lower threshold values when the car is near hoistway ends (where braking distance is constrained) and higher threshold values when the car is in positions with adequate braking distance. This allows a single governor device to provide adaptive safety responses without requiring multiple separate activation mechanisms.
2Adaptability or versatility
If mechanical activation means are used for the overspeed governor, then the activation mechanism is simple and reliable, but the governor can only be triggered at one preset speed level
Solution Approach 1:
The patent applies dynamics by transitioning from static mechanical activation to a dynamic system that can adjust the triggering speed threshold. The overspeed governor incorporates a dynamic threshold mechanism that automatically adapts the speed level at which activation occurs, based on real-time monitoring of the elevator car's position relative to the hoistway ends. This allows the same mechanical activation means to respond flexibly to different operating conditions.
Solution Approach 2:
The patent implements feedback by continuously monitoring the elevator car's position and using this information to adjust the overspeed governor's triggering threshold. The system receives feedback about the car's location and automatically modifies the speed threshold parameter accordingly - lowering the threshold when the car is near hoistway ends and maintaining higher thresholds when the car is in positions with adequate braking distance. This feedback loop enables adaptive speed level triggering without complex mechanical modifications.
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 the overspeed governor to be triggered at various speed levels, enhancing safety by providing non-contact activation and eliminating the need for additional current sources, while maintaining the reliability of traditional mechanical activation methods.
Implementation Method 1
a stator arranged to interact with the permanent magnet rotor, a winding adapted to exert, when energized, to the permanent magnet rotor a braking force that brakes movement of the permanent magnet rotor
Implementation Method 2
there is no mechanical contact in the triggering situation from stator to permanent magnet rotor, but the triggering/activation of safety gear takes place in a non-contact manner through interaction between stator and rotor
Implementation Method 3
Governor shave can rotate freely during normal elevator operation. Mechanical activation means are arranged in connection with the governor sheave. Elevator car overspeed is observed when rotating speed of the governor sheave exceed a preset threshold. In that case centrifugal force causes moving of the activation means into position that locks rotation of governor sheave
Data Source
AI summary
An overspeed governor including a governor sheave, a permanent magnet rotor coupled to the governor sheave, a stator arranged to interact with the permanent magnet rotor, a safety gear for braking movement of an elevator car and a safety rope fixed to the safety gear and arranged to run via the governor sheave. The stator includes a winding adapted to exert, when energized, to the permanent magnet rotor a braking force that brakes movement of the permanent magnet rotor and, consequently, movement of the governor sheave and the safety rope, thereby activating the safety gear.