Elevator Safety Actuator Distance Synchronization
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Solution Overview
Problem
Modern elevator systems with electronic safety actuators (ESAs) face challenges in synchronizing the engagement of safeties due to varying distances between magnet assemblies and rails, leading to potential misalignment and inefficiencies in emergency braking scenarios.
Innovation Solution
The implementation of a magnet assembly to rail distance sensing mechanism using a magnetic element and Hall Effect sensor to measure distances, allowing the control system to calculate response times and deploy braking surfaces synchronously across different distances, ensuring simultaneous engagement of safeties during over-speed or over-acceleration conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If separate magnet assemblies are deployed onto the rail using electro-magnets in an ESA system, then electronic safety actuation is achieved, but synchronization of safety engagement is compromised due to varying flight times and distances to rails
Solution Approach 1:
The system performs preliminary measurement of the distance between each magnet assembly and its corresponding rail before deployment. The control system uses these pre-measured distances to calculate and determine the optimal deployment timing for each ESA, ensuring that all safeties engage simultaneously despite different starting positions. This preliminary action eliminates the synchronization problem caused by varying flight times.
2Adaptability or versatility
If magnet assemblies are positioned at different distances from the rail, then individual ESA deployment is enabled, but synchronization of braking surface contact with the rail is degraded
Solution Approach 1:
The control system receives feedback from distance sensors that measure the gap between each magnet assembly and its corresponding rail. Based on this feedback, the controller calculates the precise deployment timing for each ESA, adjusting the activation sequence to compensate for varying distances. This feedback mechanism ensures that all braking surfaces contact their respective rails simultaneously, achieving synchronization despite different initial positions.
3Reliability
If conventional centrifugal flyweights are used to trigger switches at predetermined speeds, then mechanical safety engagement is achieved, but the system lacks the adaptability of electronic actuators
Solution Approach 1:
The patent replaces the conventional mechanical governor system with centrifugal flyweights and mechanical linkages with an electronic safety actuator system. The ESAs use electromagnetic actuators to deploy magnet assemblies onto the rail, replacing mechanical speed-sensing mechanisms with electronic sensors that measure distance and control deployment timing. This substitution maintains safety engagement reliability while adding electronic control adaptability and precision.
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 approach enhances synchronization of safety engagements, preventing excessive racking of the elevator car frame during emergency stops by accurately determining and adjusting deployment times based on measured distances, ensuring timely and coordinated action of the braking surfaces.
Implementation Method 1
The sensing system includes a sensor respectively disposed in or adjacent to each ESA. In accordance with additional embodiments, the sensor includes a magnetic element and a Hall Effect sensor.
Data Source
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AI summary
An elevator system (10) is provided and includes at least one guide rail (12). Safety features include safeties to respectively selectively impede or permit movement of an elevator car along a corresponding guide rail, and first and second electronic safety actuators (ESAs) respectively coupled to a corresponding safety. The first ESA includes a first braking surface located a first distance from the corresponding guide rail, the second ESA includes a second braking surface located a second distance from the corresponding guide rail and the first and second braking surfaces are deployable across the first and second distances, respectively, to contact the corresponding guide rails. The elevator system (10) further includes a sensing system (40) to determine the first and second distances and a control system (50) to deploy the first and second braking surfaces toward the corresponding guide rails in response to an over-speed or an over-acceleration condition with synchronization based on the first and second distances.