Air brake system is primarily used by heavy vehicles like buses and trucks which consists of different brakes like service, parking, a control pedal and an storage tank. In the parking brake, there is a disc or drum brake which is actually held by the spring pressure. Usually in trucks, the integrated air brake is known as the drum brakes. Nowadays, the use of disc brakes are very much in trend. And it is widely found in all type vehicle both light and heavy vehicles. Mostly, in heavy vehicle, the gauge is present to keep an eye on the air pressure for safety. A frequent mechanical “wig-wag” is quite common from the driver's point of view which can be easily controlled.
Advantages of air brake equipment :-
Reliability- As compared to hydraulic brake air brake is much reliable. It is very powerful and provides good control over the vehicle. In case of any fault or leakage, the brakes turns back to its default position which allows good control over the vehicle.
Cost Effective – Air Brake is cost-effective. Since its operating medium is air and the air costs nothing. The free availability of air proves the product to be inexpensive. Any leakage or breakage does not lead to heavy loss. Brake system can be easily managed, maintained and adjusted in case of minor or major fault.
Safety- Air Brake equipment is safe for usage. It is always available with safety measure which is known as spring brakes. The spring air automatically gets activated when there is no air. In case of availability of sufficient amount of air for regular brakes, spring air is compressed.
Following components are exclusive foundation air-brake system in a truck or a bus:
Air compressor: It is used in brake system to pump the air into storage tanks
Air compressor governor: Helps control the cut-in and cut-out point of the air compressor and also maintains a specified amount of air in the tank.
Air reservoir tanks: It holds compressed air which used by the braking system
Drain valves: It is used to drain the air when the vehicle is not in use
Foot valve (brake pedal): It helps in releasing air from the reservoir tank.
Brake chambers: It is a cylindrical container that houses a slack adjuster that helps move a diaphragm mechanism
Push rod: It is a steel rod similar to a piston that helps connect the brake chamber to the slack adjuster.
Slack adjusters: It is an arm that connects the push rod to the brake. It adjusts the distance between the brake shoes
Brake S-cam: It is an s-shaped cam which supports in pushing the brake shoes apart and against the brake drum
Brake shoe: It is a steel mechanism with a lining. It causes friction against the brake drum
Return spring: It is a stiff spring connected to each of the brake shoes.