Elevator Governor Flyweight Rest Position Design
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Solution Overview
Problem
Low-to-midrise elevator systems are prone to false activation of the over speed governor due to passenger-induced vertical oscillations, leading to unnecessary emergency stops and service interruptions.
Innovation Solution
An improved elevator governor design featuring flyweights with a biasing spring system and flyweight position members that maintain stability by limiting the range of motion, ensuring consistent activation speed and preventing false actuations from abnormal passenger behavior-induced vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the governor allows flyweights to move freely between initial and activation positions, then the governor can detect over-speed conditions, but the system becomes sensitive to oscillations causing false activation
Solution Approach 1:
The flyweight position member pre-positions the flyweight at a rest position that is offset from the initial position toward the activation position. This preliminary positioning ensures that during normal oscillations, the flyweight cannot reach the activation position, preventing false governor activation while maintaining the ability to detect true over-speed conditions.
Solution Approach 2:
The flyweight position member acts as an intermediary element between the flyweight and the activation position. It limits the range of motion of the flyweight by providing a mechanical stop at the rest position, thereby preventing direct contact between oscillations and the activation threshold while still allowing over-speed detection.
2Stability of the object's composition
If the biasing member uses a spring with high tension to resist flyweight movement, then the governor remains stable during oscillations, but the activation speed becomes inconsistent
Solution Approach 1:
The spring is pre-stretched to a second length that corresponds to the rest position, creating a second induced tension that is higher than the first induced tension at the initial position. This preliminary tensioning provides stable resistance during oscillations while the flyweight position member ensures consistent activation by limiting the range of motion.
Solution Approach 2:
The spring constant and length are specifically selected to create different tension levels at different positions. The spring is designed with parameters that induce a first tension at the initial position and a higher second tension at the rest position, allowing stable operation during oscillations while maintaining precise activation speed.
3Speed
If the flyweight can move the full distance from initial to activation position, then the governor responds to speed changes, but oscillations cause unnecessary emergency stops
Solution Approach 1:
The flyweight position member pre-limits the range of motion to a second, shorter distance between the rest position and activation position. This preliminary limitation prevents oscillations from causing full travel to the activation position, eliminating false emergency stops while preserving the governor's ability to respond to true over-speed conditions.
Solution Approach 2:
The flyweight position member serves as an intermediary that modifies the relationship between flyweight movement and governor activation. By establishing a rest position that is offset from the initial position, it creates a buffer zone that prevents oscillations from triggering activation while allowing legitimate speed threshold detection.
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 enhances the governor's stability and consistency, reducing false brake applications and maintaining elevator service availability by ensuring that the flyweights activate only when the elevator exceeds the predefined speed threshold, thus minimizing service disruptions.
Implementation Method 1
A biasing member biases the at least one flyweight toward the initial position. The biasing member is configured to allow the at least one flyweight to reach the activation position when the elevator speed reaches the predefined threshold.
Implementation Method 2
at least one flyweight configured to move a first distance between an initial position corresponding to a zero speed condition and an activation position corresponding to an elevator speed that reaches a predefined threshold
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An illustrative example elevator governor (30) includes at least one flyweight (34, 36, 38) configured to move a first distance between an initial position corresponding to a zero speed condition and an activation position corresponding to an elevator speed that reaches a predefined threshold. A biasing member (44, 46, 48) biases the at least one flyweight toward the initial position. The biasing member is configured to allow the at least one flyweight to reach the activation position when the elevator speed reaches the predefined threshold. A flyweight position member (60) sets a rest position of the at least one flyweight in the zero speed condition that is between the initial position and the activation position. A range of motion of the at least one flyweight is limited to a second, shorter distance between the rest position and the activation position.