Compact Elevator Governor with Aligned Flyweights
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Solution Overview
Problem
Elevator governors face challenges in space requirements and false trips, with pendulum-type governors needing significant space and flyweight-type governors being prone to unnecessary stoppages due to sensitivity to acceleration and deceleration.
Innovation Solution
A compact elevator governor design with a sheave and flyweight having aligned centers of gravity, using a spring-biased linkage system and sensors to prevent overspeed, reducing space needs and false trips by ensuring precise engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pendulum-type governor is used, then the governor can effectively slow down and stop the elevator car, but the space requirement increases significantly due to the need for vertical shaft and gearbox
Solution Approach 1:
The patent replaces the complex mechanical transmission system (vertical shaft and gearbox) of traditional pendulum governors with a directly mounted flyweight mechanism on the sheave. This substitution eliminates the need for additional mechanical components while maintaining the overspeed control function, thereby reducing space requirements.
Solution Approach 2:
The patent merges the governor mechanism directly with the sheave by mounting the flyweights on the sheave itself. This integration combines two previously separate components (sheave and governor mechanism) into a single unified structure, eliminating the need for separate vertical shafts and gearboxes, thus reducing overall space occupation.
2Volume of moving object
If a flyweight-type governor is used, then the space requirement is reduced compared to pendulum-type governors, but the governor becomes more prone to false trips due to sensitivity to acceleration and deceleration
Solution Approach 1:
The patent employs counterbalancing weights that are strategically positioned to offset the effects of acceleration and deceleration forces. These counterweights create opposing forces that cancel out the spurious signals that would otherwise trigger false trips, allowing the governor to distinguish between normal operational variations and genuine overspeed conditions.
Solution Approach 2:
The patent applies different properties to different parts of the flyweight mechanism. Specifically, the flyweights are designed with asymmetric mass distribution and are positioned at specific locations on the sheave to create differential responses to various operational conditions. This local differentiation allows the system to be sensitive to overspeed while insensitive to normal acceleration and deceleration.
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 solution provides a compact governor with reduced space requirements and minimized false trips, ensuring safe and reliable speed regulation of elevator cars.
Implementation Method 1
As the sheave and flyweights rotate, centrifugal force tends to cause the flyweights to pivot radially outwardly. The spring is sized such that its biasing force is overcome when the sheave rotates beyond a predetermined safe speed and thus the generated centrifugal force is greater than the spring biasing force.
Implementation Method 2
a biasing element exerting a radially inward force on the flyweight
Data Source
Figure 1
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AI summary
A governor system for an elevator is disclosed. The governor includes a shaft horizontally extending from a sheave of the governor system. A base, spring, and slider are mounted on the shaft with linkages extending from the base of the sheave to at least one flyweight. The spring and flyweights are sized such that centrifugal force will be sufficient to overcome the biasing force of the spring upon the sheave reaching a certain rotational speed. Overspeed sensors and mechanical switches are positioned proximate the flyweights and flyweights plates such that upon such motion of the flyweights, the governor system is triggered, thereby slowing and ultimately stopping the elevator. The governor system has a greatly reduced space requirement compared to previous governors, as well as a reduced likelihood of false trips due to acceleration or deceleration of the car.