What is spring brakes?

Spring brakes are a type of parking brake system used in heavy-duty vehicles, such as trucks and buses. Also known as emergency brakes or parking brakes, they provide an additional safety measure for keeping the vehicle stationary when parked or in case of a failure in the service brake system.

Here are some key points about spring brakes:

1. How they work: Spring brakes use a mechanical spring to apply the brakes when the air pressure in the brake system drops below a certain threshold. When the parking brake is engaged, the mechanical spring compresses, forcefully applying the brakes to prevent the vehicle from moving.

2. Purpose: The primary purpose of spring brakes is to serve as a parking brake. They ensure the vehicle stays stationary when parked, even if there is a failure or loss of air pressure in the service brake system. Additionally, they act as an emergency backup in case the main braking system fails.

3. Construction: Spring brakes consist of a diaphragm, a mechanical spring, a parking brake chamber, and brake shoes. The diaphragm relies on air pressure to keep the spring compressed. When the pressure drops below a specific level, the diaphragm allows the spring to expand and apply the brakes.

4. Safety features: Spring brakes include safety mechanisms to prevent accidental release. These mechanisms include locks, which keep the spring in a compressed position until the air pressure is restored. Additionally, some systems have an indicator to show if the parking brake is engaged or disengaged.

5. Required maintenance: Regular inspection and maintenance of spring brakes are crucial to ensure their proper functioning. This includes checking for proper adjustment, signs of wear, and damage. The proper lubrication of brake components is also essential to prevent sticking or seizing.

6. Regulatory requirements: Spring brakes are mandatory in commercial vehicles and are regulated by various transportation authorities, such as the Department of Transportation (DOT) in the United States. They must meet specific standards for performance and safety.

In summary, spring brakes are an essential component in heavy-duty vehicles, providing a reliable parking brake system and emergency backup in case of service brake failure. Regular inspection and maintenance are necessary to ensure their proper functioning and adherence to regulatory requirements.