Elevator Governor Direction-Dependent Overspeed Detection
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Solution Overview
Problem
Conventional elevator governors lack rotation direction dependence in overspeed detection, leading to inefficiencies and increased costs due to unnecessary redundant configurations and part wear, particularly when ascent speeds exceed descent speeds.
Innovation Solution
An elevator governor design incorporating a sheave with fly-weights that adjust outward based on rotation speed, a balance spring to center the fly-weight, and a stopper to prevent excessive outward movement, allowing for direction-dependent overspeed detection without compromising reliability or generating vibrations and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a car-side governor uses a single overspeed detection mechanism adapted to descent speed, then the descent speed detection is accurate, but it cannot perform overspeed detection adapted to ascent speed when ascent speed is higher than descent speed
Solution Approach 1:
The governor mechanism dynamically adapts its detection characteristics based on rotation direction. The fly-weight mechanism responds differently to centrifugal forces generated during ascent versus descent, enabling direction-dependent overspeed detection thresholds without requiring separate static mechanisms for each direction.
Solution Approach 2:
A single governor mechanism performs multiple functions: it detects overspeed conditions for both ascent and descent operations, but with direction-adapted detection characteristics. The same physical mechanism serves both directional detection needs through its dynamic response to rotation direction and speed.
2Adaptability or versatility
If two independent overspeed detection mechanisms are provided with different detection operation speeds, then overspeed detection adapted to each ascent and descent speed is achieved, but the ratchet becomes free during rotation in one direction causing vibrations and noises
Solution Approach 1:
The harmful ratchet component is completely removed from the governor mechanism. Instead of using a ratchet to prevent reverse rotation, the invention employs a purely centrifugal fly-weight mechanism that responds only to rotation speed and direction, eliminating the source of vibrations and noises while maintaining directional detection capability.
Solution Approach 2:
The invention converts the potentially harmful free-ratchet condition into a beneficial feature by eliminating the ratchet entirely. The mechanism now benefits from smooth, vibration-free operation while the fly-weight's natural centrifugal response provides the necessary directional detection without mechanical interference.
3Adaptability or versatility
If two independent overspeed detection mechanisms are provided with different detection operation speeds, then overspeed detection adapted to each ascent and descent speed is achieved, but wear of ratchet parts increases decreasing safety and reliability
Solution Approach 1:
The wear-prone ratchet component is completely removed from the governor mechanism. Instead of using a ratchet to prevent reverse rotation, the invention employs a purely centrifugal fly-weight mechanism that responds only to rotation speed and direction, eliminating the source of vibrations and noises while maintaining directional detection capability.
Solution Approach 2:
The mechanical ratchet-and-pawl system is replaced with a centrifugal fly-weight mechanism. This substitution eliminates mechanical wear from ratchet engagement while maintaining the ability to detect rotation direction and speed, thereby improving reliability through a wear-free detection system.
4Reliability
If a weight-side governor is provided for elevators with ascent speed higher than descent speed, then overspeed detection in ascent direction is achieved, but the configuration becomes redundant resulting in high cost
Solution Approach 1:
A single car-side governor mechanism performs the function of both ascent and descent overspeed detection by adapting its response based on rotation direction. The fly-weight mechanism universally detects overspeed conditions in both directions without requiring separate weight-side and car-side governors, eliminating redundancy while maintaining comprehensive safety coverage.
Solution Approach 2:
The functions of separate car-side and weight-side governors are merged into a single car-side governor with direction-adapted detection capability. This consolidation eliminates the need for redundant weight-side governor hardware while maintaining overspeed detection coverage for both ascent and descent operations.
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
This configuration enables efficient, direction-dependent overspeed detection with reduced part wear and noise, maintaining reliability while simplifying the system and avoiding redundant configurations, thus optimizing performance and cost-effectiveness.
Implementation Method 1
a fly-weight which is provided in the sheave and increases and decreases an outward moving quantity in response to an increase and decrease in the rotation speed of the sheave
Data Source
Figure 1
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AI summary
Provided is an elevator governor capable of achieving, with a simple configuration, an overspeed detection mechanism to which rotation dependence is added while preventing a decrease in reliability due to the generation of vibrations and noises and the wear of parts. For this purpose, the elevator governor includes: a sheave on which a rope moving in response to the movement of an ascending and descending body of an elevator is wound, and which changes the rotation speed in one direction in response to the ascent speed of the ascending and descending body and changes the rotation speed in the other direction in response to the descent speed of the ascending and descending body; a fly-weight which is provided in the sheave and increases and decreases an outward moving quantity in response to an increase and decrease in the rotation speed of the sheave; a detector which is provided in proximity to the fly-weight and performs overspeed detection of the sheave when the fly-weight has moved outward by a predetermined quantity; and a stopper which is provided in proximity to the fly-weight and prevents the fly-weight from moving outward more than or equal to the predetermined quantity while the sheave is rotating in a predetermined direction which is either of the two rotation directions.