Elevator Governor with Dual Tripping Mechanisms
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Solution Overview
Problem
Existing elevator systems face challenges in achieving specific control over speed when using a single governor tripping mechanism for both activating the machine brake and engaging supplemental brakes, particularly in low-speed elevators, where independent control over over-speed conditions is difficult to achieve.
Innovation Solution
The implementation of separate governor tripping mechanisms, each supported on its own sheave, with centrifugal elements biased by different magnetic forces, allowing for independent control over activation thresholds for the machine brake and supplemental brake functions, enabling precise control over elevator car speed in specific directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single governor tripping mechanism is used for both activating the machine brake and engaging supplemental brakes, then the device complexity is reduced, but the control precision over activation speeds deteriorates
Solution Approach 1:
The governor system is segmented into two independent tripping mechanisms: a first tripping mechanism on a first governor sheave for activating the machine brake, and a second tripping mechanism on a second governor sheave for engaging supplemental brakes. Each mechanism can be independently adjusted to trip at different speed thresholds, enabling precise control over activation speeds while maintaining separate functional control.
2Ease of operation
If a single governor tripping mechanism is used for both functions, then the ease of operation is improved, but the reliability of speed protection deteriorates
Solution Approach 1:
The governor system is divided into two independent tripping mechanisms that can operate autonomously at different speed thresholds. This segmentation ensures that if one mechanism fails or does not trip at the appropriate speed, the other mechanism remains available to provide protection, thereby enhancing the overall reliability of the speed protection system.
Solution Approach 2:
The system provides a staged protection approach where the first tripping mechanism activates the machine brake at a lower speed threshold as a preliminary protective measure, while the second tripping mechanism engages supplemental brakes at a higher speed threshold as a backup protective measure. This layered approach ensures reliable protection across multiple speed violation scenarios.
3Measurement precision
If separate governor tripping mechanisms on separate sheaves are used, then the control precision over activation speeds is improved, but the device complexity increases
Solution Approach 1:
Both governor sheaves and their associated tripping mechanisms are designed to perform the same fundamental function of speed monitoring and tripping, but with different adjustable thresholds. This universality allows the system to achieve precise control over multiple activation speeds using replicated, standardized components rather than fundamentally different mechanisms, thereby limiting the increase in complexity.
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 solution provides independent and flexible control over the activation of the machine brake and supplemental brakes at distinct threshold speeds, enhancing the reliability and accuracy of speed management in elevator systems, particularly in low-speed scenarios.
Implementation Method 1
The first and second governor tripping mechanisms may comprise centrifugal elements that are biased into a first position relative to the corresponding governor sheave, the centrifugal elements moving outward toward a second position responsive to movement of the elevator car near the corresponding threshold speed
Implementation Method 2
The biasing member of each governor tripping mechanism may comprise a magnet and a magnetic force of the magnet of the first governor tripping mechanism is lower than a magnetic force of the magnet of the second governor tripping mechanism
Data Source
Figure 1
Figure 2~3
AI summary
An exemplary elevator system includes an elevator car. A first governor sheave is supported on the elevator car for movement with the elevator car. The first governor sheave is supported for rotational movement relative to the elevator car responsive to movement of the elevator car. A first governor tripping mechanism is supported on the first governor sheave. The first governor tripping mechanism provides an indication to perform a first governor function for controlling the speed of the elevator car responsive to the elevator car moving at a speed above a first threshold speed. A second governor sheave is supported on the elevator car for movement with the elevator car and for rotational movement relative to the elevator car responsive to movement of the elevator car. A second governor tripping mechanism is supported on the second governor sheave. The second governor tripping mechanism provides an indication to perform a second governor function for controlling a speed of the elevator car responsive to the elevator car moving at a speed above a second threshold speed.