Abstract: The present invention is a fast acting pneumatic brake system for vehicles. The system includes an pneumatic spring brake operatively coupled to a first and second air tank via supply and constant pressure air lines, respectively. A pneumatically controlled central air valve is operatively coupled to the supply air line. The central air valve is operatively coupled to a hand valve which controls the operation of the central valve. A first electrically controlled air valve is operatively coupled to the supply air line between the pneumatic spring brake and the pneumatically controlled air valve. The first electrically controlled valve is a normally open valve which closes only when energized. A second electrically controlled air valve is operatively coupled to the constant pressure air line between the pneumatic spring brake and the second air tank. The second electrically controlled air valve is a normally closed valve which opens only when energized.

Abstract: An improved air brake system for tractor trailers is disclosed. The present system immediately engages the trailer brakes of a tractor trailer when an emergency brake control member is engaged by the driver. The trailer brake is operatively coupled to a spring brake having a first spring operatively coupled to the trailer brake, the first spring engaging the trailer brake when the spring is in a relaxed position. The spring brake also has a first pneumatic chamber having a first movable diaphragm, the movable diaphragm causing the first spring to compress and disengage the brake when the first chamber is compressed with air supplied by an air line. Decompression of the first pneumatic chamber permitting the first spring to relax.