Elevator Rescue Brake Release Timing for Safe Car Speed
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Solution Overview
Problem
Elevator systems face challenges in determining an optimal rescue time period for moving a stalled elevator car during an emergency stop, as standard periods may not account for the specific conditions of each system, leading to potential excessive speed and brake wear.
Innovation Solution
A method to learn and set a rescue time period by releasing the machine brake for test periods, detecting maximum travel speeds, and checking if they are acceptable, optimizing the rescue time period for the specific elevator installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-set rescue time period is used, then the rescue operation can be performed, but the brake wear is excessive and the speed may be uncontrollably high
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the rescue time period based on detected elevator car speed. The system measures the actual speed of the elevator car during rescue operation and modifies the brake release time accordingly, transforming the fixed pre-set time period into a variable parameter that adapts to real-time conditions, thereby reducing brake wear while maintaining safe operation
Solution Approach 2:
The patent implements feedback control by continuously monitoring the elevator car speed during the rescue operation and using this information to adjust the brake release duration. The speed detection system provides real-time feedback to the control mechanism, enabling the system to learn and optimize the rescue time period for each specific installation, preventing excessive brake wear and unsafe speeds
2Reliability
If a pre-set rescue time period is used, then the rescue operation can be performed, but the speed control is insufficient and passenger safety is compromised
Solution Approach 1:
The patent uses feedback control by continuously monitoring elevator car speed during rescue operation and adjusting the brake release time based on the detected speed. This closed-loop control ensures the elevator car speed remains within safe limits while still achieving movement for passenger rescue
Solution Approach 2:
The system dynamically changes the rescue time period parameter based on actual speed measurements. By adjusting this parameter in real-time according to the elevator car's response, the system achieves precise speed control that maintains passenger safety while ensuring effective rescue operation
3Length of moving object
If the rescue time period is extended to ensure movement, then the movement distance increases, but the maximum speed reached becomes excessively high
Solution Approach 1:
The patent applies parameter changes by adjusting the brake release time period based on the relationship between movement distance and maximum speed. The system learns the optimal time period that achieves sufficient movement for rescue while limiting the maximum speed to acceptable levels, transforming the fixed time parameter into an optimized variable
Solution Approach 2:
The patent applies partial action by releasing the brake for just the necessary duration to achieve sufficient movement for rescue, rather than using a fixed extended time period. This optimized partial release achieves the minimum required movement while avoiding the excessive speed that would result from longer brake release durations
Data Source
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AI summary
A method of learning a rescue time period by an elevator system (101). The elevator system (101) includes an elevator car (103) moved by a machine (111) and a machine brake (120), arranged such that braking of the machine (111) by the machine brake (120) brakes motion of the elevator car (103). The method includes releasing the machine brake (120) for at least one test time period, at the end of which the machine brake (120) is engaged, detecting a corresponding at least one maximum travel speed of the elevator car (103) reached as a result of releasing the machine brake (120) for each at least one test time period, checking whether each at least one maximum travel speed is an acceptable speed, and setting the rescue time period based upon said checking.