Patent ID: 7216941

Claim:
An automatic parking brake application system with manual disengage for a motor vehicle, the system comprising: a compressed air source; a push-pull valve having an inlet and an outlet; a parking brake spring chamber having an inlet coupled to the outlet from the push-pull valve; a first air delivery line coupled to supply compressed air from the compressed air source to the inlet of the push-pull valve; a first piloted lock-in valve having an inlet, an outlet, a control port and an exhaust port, with the inlet connected to receive air from the compressed air source and the outlet connected to the inlet to the push-pull valve; a first check valve connected to pass air from the outlet of the piloted lock-in valve back to the first air delivery line between the compressed air source and the inlet to the first piloted lock-in valve; a solenoid actuated control port valve responsive to at least a first interlock signal for applying compressed air to the control input of the first piloted lock-in valve; and a first solenoid actuated control valve connected to the exhaust port of the first piloted lock-in valve, the solenoid actuated control valve being connected for response to at least a first selected actuation signal.