Abstract: An air brake safety and parking mechanism is provided in the form of an emergency braking system which operates automatically to set and latch the air brakes of a vehicle in a braking position whenever the air pressure of the service braking system of the vehicle drops below a predetermined threshold, and which may be set and released mechanically for parking purposes. The air brake safety mechanism of the invention includes an antifriction ball screw coupled to the air brake piston in the air brake chamber of the vehicle braking system, and extending along a selected axis into an air-tight housing which is mounted adjacent to the brake chamber. A ball nut is rotatably mounted in the housing in threaded relationship with the screw to permit linear movement of the screw in both directions along the selected axis so long as the nut is freely rotatable.

Abstract: An air brake safety and parking mechanism is provided in the form of an emergency braking system which operates automatically to set and latch the air brakes of a vehicle in a braking position whenever the air pressure of the service braking system of the vehicle drops below a pre-selected threshold, and which also can be set and released mechanically for parking purposes. The mechanism includes an aperatured latch through which an actuating rod for the air brakes of the vehicle extends and is freely slidable so long as the latch is in a first angular position, but which is engaged by the latch when the latch is in a second angular position to prevent movement of the rod in a direction which would release the brakes of the vehicle. A feature of the mechanism is that it can subsequently be released and then re-set so that the brake can be used for parking purposes, for example, for a trailer.