An Automatic Rescue Device (ARD) is a safety device used in elevators (also known as lifts) to ensure the safety of passengers and prevent them from being trapped in case of a power failure or other mechanical issues. It is designed to bring the elevator to a designated level, typically the nearest floor, and open the doors, allowing passengers to exit safely.

Here's how an Automatic Rescue Device typically works:

1. Power Failure Detection: When a power failure occurs, the ARD detects the loss of power and immediately activates.

Power Supply: The ARD is equipped with its own power source, usually a rechargeable battery. This power source provides the necessary energy to operate the rescue process.

Controlled Descent: If the elevator is in motion at the time of the power failure, the ARD takes control of the elevator's movement and initiates a controlled descent to the nearest floor.

Door Opening: Once the elevator reaches the designated level, the ARD ensures that the doors are opened, allowing passengers to safely exit the elevator car.

Manual Reset: After the passengers have exited the elevator, the ARD may need to be manually reset or serviced by maintenance personnel to restore normal elevator operation.

The Automatic Rescue Device is an important safety feature in modern elevator systems, providing a way to mitigate the risks associated with power failures or other emergencies. It helps prevent passengers from being trapped inside elevators and ensures their safety until they can be safely evacuated.