A hand brake is also known as a parking brake or emergency brake. It's a secondary braking system used to keep a vehicle in a stationary position. A hand brake is usually installed as a lever situated between the front seats and is activated by pulling it up.
The parking brake system consists of a cable linked from the lever to the brake mechanism at the rear wheels. The brake force is distributed evenly to both of the wheels through a U-shaped equalizer.
In the United States, most cars are equipped with drum brakes at the rear as standard, as they cost less and can act as parking brakes as well. The parking brake cable bypasses the hydraulic brake system and reaches directly to the brake shoes in the drum, ensuring the vehicle stays stationary.
On the other hand, vehicles with rear disc brakes need a separate parking brake mechanism, as the parking brake is actuated through the brake caliper instead. The caliper piston needs an additional lever and corkscrew. The lever pushes the corkscrew toward the direction of the caliper piston when the hand brake is pulled.
Nowadays, some car manufacturers eliminate the hand brake and adopt an electric parking brake system. This brake mechanism works similarly to the traditional hand brake, but instead of using a stick or lever, the system is actuated electrically via a button.