Patent ID: 8974011
Filing Date: 2015-03-10
Classification: B60T

Abstract:
1. A vehicle brake system comprising: a hydraulic pump; a sump; a left brake pedal; a right brake pedal operable independently of the left brake pedal; a left brake unit; a right brake unit; a left manually operated brake valve operable only by the left brake pedal and having a first pressure responsive pilot acting in opposition to a left manual actuator; a right manually operated brake valve operable only by the right brake pedal and having a second pressure responsive pilot acting in opposition to a right manual actuator; a solenoid operated left on-off non-proportional valve having a first port connected to the first pilot, a second port, a third port connected to left brake unit, a solenoid and a spring which opposes the solenoid; a solenoid operated right on-off non-proportional valve having a first port connected to the second pilot, a second port, a third port connected to right brake unit, a solenoid and a spring which opposes the solenoid; a pair of solenoid operated proportional valves, each proportional valve controlling communication between the pump, the sump and the second port of a corresponding one of the on-off valves.