Elevator Brake Control for Emergency Rescue
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Solution Overview
Problem
Elevators often stop outside landing areas during emergencies, and existing safety systems fail to ensure safe and controlled movement of the elevator car to end buffers, posing challenges for rescuing trapped individuals, especially when power is off and overspeed governors are not usable.
Innovation Solution
A method where a manual brake opening device, connected to an end limit indicator detection system, automatically reduces the elevator car's speed by actuating the electric brake when approaching end buffers, ensuring a safe and controlled approach to landing areas, even in power-outage scenarios, using an independent emergency power supply and intermittent brake operation to prevent overspeed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the elevator car is moved manually to the end of the car path after stopping outside a landing area, then trapped persons can be released, but the car or counterweight may enter the upper and lower end regions of the shaft where end buffers are located, creating a safety risk
Solution Approach 1:
The end limit indicator is positioned in advance before the end buffer location, and the brake operator is configured to activate the electric brake when the car approaches this predetermined position. This preliminary action ensures speed reduction occurs before the car reaches the dangerous end buffer region, allowing safe manual rescue operation without risking buffer collision.
2Speed
If the overspeed governor is used to reduce counterweight speed during manual rescue operation, then speed control is achieved, but the governor cannot be used when the car approaches end buffers because it requires approach speed below the limit speed
Solution Approach 1:
The brake operator serves as an intermediary device between the manual brake opening device and the electric brake system. When the end limit indicator detects approach to the end buffer region, the brake operator automatically activates the electric brake to reduce speed, providing the necessary speed control in the end buffer approach scenario where the overspeed governor cannot be used.
3Reliability
If the electric brake is activated to stop the elevator car during emergency situations, then the car stops, but it normally doesn't stop in the entrance/exit area of a landing, requiring manual intervention
Solution Approach 1:
The brake operator is configured to automatically activate the electric brake when the end limit indicator signals approach to the end buffer region. This self-service function eliminates the need for manual brake opening intervention by service technicians, as the system automatically provides the necessary speed reduction and stopping control during emergency situations.
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
Enables safe and controlled movement of the elevator car to end buffers, allowing for the release of trapped individuals without manual mechanical intervention, ensuring reduced speed and preventing overspeed activation, even during power outages, by integrating end limit indicator detection and independent emergency power supply.
Implementation Method 1
the electric elevator brake, usually two electric elevator brakes, are activated (deenergized) as to grip a rotating part of the drive, for example the traction sheave, to stop the elevator car
Implementation Method 2
the manual brake opening device, for example an electric brake operator, is connected to a end limit indicator detection means, which issues an end limit signal when getting into the vicinity of an end limit indicator located at the upper and/or lower shaft end
Data Source
AI summary
A method is provided for moving an elevator car in a rescue operation after at least one electric elevator brake have been actuated, whereafter the brake is re-opened via a manual brake opening device and operated to allow a movement of the elevator car to a next landing. The manual brake opening device is connected to an end limit indicator detector, which end limit indicator detector is configured to issue an end limit signal when elevator car arrives at an area of an end limit indicator at the end of its movement range of the elevator car in the elevator shaft. When the end limit indicator detector outputs an end limit signal to the manual brake opening device, the elevator brake is actuated by the manual brake opening device to stop the elevator car.