Elevator Overspeed Governor with Electronic RPM Sensor
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Solution Overview
Problem
Conventional overspeed governors in elevators exhibit acceleration-dependent behavior, leading to delayed and less precise response to speed exceedances due to their reliance on centrifugal force and mass inertia, necessitating a more precise and instantaneous speed detection mechanism.
Innovation Solution
The implementation of contactless RPM sensors and associated electronics, coupled with a clutch system that generates actuating energy internally, allowing for precise speed detection and rapid activation of the braking mechanism with minimal auxiliary energy, enabling self-reinforcement and automatic continuation of the braking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical speed limiters using centrifugal force and mass inertia are used, then the system is simple in structure and mechanically reliable, but the response to overspeed conditions is delayed and acceleration-dependent
Solution Approach 1:
The patent replaces the conventional mechanical centrifugal force-based detection system with an electronic RPM sensor system. The sensor detects rotational speed of the sheave directly, converting mechanical motion into electrical signals for immediate processing, thereby eliminating the inherent time delay and acceleration-dependency of mechanical inertia-based systems while maintaining operational reliability.
Solution Approach 2:
The system uses the rotational motion of the sheave itself to generate the detection signal through the RPM sensor, without requiring separate power sources or external actuation for speed detection. The brake mechanism also utilizes the system's own kinetic energy and friction to achieve self-reinforcement and automatic continuation of the braking process once initiated.
2Device complexity
If conventional mechanical braking mechanisms are used, then the system is simple and mechanically robust, but the device requires more space and generates higher stress on components
Solution Approach 1:
The patent replaces extensive mechanical linkages, centrifugal masses, and complex trigger mechanisms with compact electronic components including RPM sensors, evaluation electronics, and a clutch mechanism. This substitution dramatically reduces the spatial requirements while maintaining the essential mechanical braking function through a more space-efficient electronic control architecture.
3Reliability
If conventional mechanical speed detection mechanisms are used, then the system is mechanically robust, but the speed detection is less precise and slower
Solution Approach 1:
The patent replaces mechanical speed detection methods with electronic RPM sensors that provide precise, real-time measurement of sheave rotational speed. The electronic evaluation unit processes these signals to detect overspeed conditions with higher precision and faster response, while the mechanical robustness is maintained in the brake and sheave components that bear the operational loads.
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 a more precise and immediate response to overspeed conditions, reducing the risk of accidents by ensuring timely activation of the braking system, while also allowing for a more compact design and reduced stress on components, thus enhancing safety and reliability.
Implementation Method 1
The brake shoe, which, unlike the previous brake shoes designed as part of a centrifugal mass system, is stationary until it is activated, is thereby—preferably indirectly—deflected by the rotating component and brought into contact with the brake rotor
Implementation Method 2
A clutch works in a functional network with the speed sensor and the associated electronics. This can be controlled by the electronics and, when activated, couples at least one brake shoe—preferably indirectly—to a rotating component of the speed limiter
Data Source
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AI summary
The trigger system rotary speed sensor, preferably operates without mechanical contact. It produces a signal which is evaluated in coupled electronics. The system also includes an electronically-controlled auxiliary coupling (H). When triggered, this brings a brake jaw into contact with a rotor (7) of the speed limiter. This causes the brake jaw unit (12) to pivot and rest against the rotor (7) such that self-intensification of the braking force results. As a result, the rope pulley (4a, 4b) is braked.