Elevator Brake Controller Position-Based Delay Logic
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Solution Overview
Problem
Elevator systems face challenges in controlling the machine brake during emergency stops, leading to abrupt stops that cause passenger discomfort and potential adverse interactions with other components, such as buffers, due to the inability to smoothly apply braking forces.
Innovation Solution
An elevator system with a brake controller that uses detectors to determine the position of the elevator car and selectively enables or disables a delay in brake application based on its position relative to the travel path ends, ensuring a smooth stop while preventing adverse contacts with buffers or other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the machine brake is applied immediately during emergency stop conditions, then the elevator car stops quickly, but the stop becomes very abrupt causing passenger discomfort and unease
Solution Approach 1:
The system performs preliminary action by delaying brake application for a predetermined time period (e.g., 500ms to 2 seconds) after detecting emergency stop conditions. This delay allows the motor to complete its deceleration profile naturally, and only then does the brake engage to hold the car. This preliminary delay action smooths the stopping process and reduces abruptness, directly resolving the contradiction between quick stopping and passenger comfort.
2Ease of operation
If the machine brake application is delayed to improve stop smoothness, then passenger comfort improves, but the elevator car may contact buffers or other components adversely
Solution Approach 1:
The system uses feedback from detectors (such as limit switches or position sensors) that monitor the elevator car's position relative to buffers and other components. This feedback information is fed back to the brake controller, which uses it to dynamically adjust or cancel the brake delay command when unsafe conditions are detected. This closed-loop feedback mechanism ensures that passenger comfort through delay is maintained only when safe, resolving the contradiction between comfort and reliability.
Solution Approach 2:
The brake delay command is made dynamic rather than static. The system continuously evaluates safety conditions and adjusts the delay parameter in real-time: applying delay when safe to improve comfort, and canceling delay when unsafe to prevent component contact. This dynamic adaptation resolves the contradiction by making the brake response flexible based on real-time system state.
3Measurement precision
If the brake controller uses detectors to determine car position and selectively enable/disable delay commands, then control precision improves, but device complexity increases
Solution Approach 1:
The brake controller is designed with multi-functionality, serving both as a brake actuator and as a position-based decision-making unit. By integrating the position evaluation logic and delay command management within the existing brake controller (rather than adding separate dedicated systems), the patent achieves precise position-based control while minimizing the increase in overall device complexity. The detector infrastructure is leveraged for dual purposes: normal operation monitoring and emergency stop safety assessment.
Data Source
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AI summary
An illustrative elevator system (20) includes an elevator car (22), a machine (30) including a motor (32) that provides a motive force for moving the elevator car (22) along a travel path and a brake (36) that resists movement of the elevator car (22), and a brake controller (40). The brake controller (40) is configured to determine when the elevator car (22) is within a selected range (54, 58) of at least one end of the travel path. The brake controller (40) inhibits a delay in application of the brake (36) when the elevator car (22) is within the selected range (54, 58) and permits a delay in application of the brake (36) when the elevator car (22) is outside of the selected range (54, 58).