Abstract: A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

Abstract: A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

Abstract: A method of detecting a leak in an air trailer brake circuit of a trailer includes providing a controller, a base valve, a first sensor, a second sensor, a leak control valve having a solenoid, a pneumatic fluid supply, a first brake output, and a second brake output. The method further includes supplying a first pressure to an inlet of the base valve and outputting a second pressure from an outlet of the base valve. The first pressure is detected with the first sensor and the second pressure is detected with the second sensor. The method also includes communicating the detected first pressure and the second pressure to the controller, and comparing a difference between first pressure and the second pressure to a threshold. A leak is detected in the air trailer brake circuit if the difference satisfies the threshold.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A method of detecting a leak in a hydraulic trailer brake circuit of a trailer includes providing a controller, a base valve, a first sensor, a second sensor, a control valve having a solenoid, a reduction valve, a hydraulic fluid supply, a first brake output, and a second brake output. The method also includes supplying a first pressure to an inlet of the base valve and outputting a second pressure from an outlet of the base valve to the first brake output. The first pressure is detected by the first sensor and the second pressure is detected by the second sensor, and the detected first and second pressures are communicated to the controller. The difference between the first and second pressures are compared to a threshold, and a leak is detected in the hydraulic trailer brake circuit if the difference satisfies the threshold.

Abstract: A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

Abstract: A braking system of a trailer and work machine includes a pressurized fluid supply, a hydraulic base valve fluidly coupled to the supply, and a pneumatic base valve fluidly coupled to the supply. A proportional control valve is also fluidly coupled to the supply, and it includes an outlet disposed in fluid communication with the inlets of the hydraulic base valve and the pneumatic base valve. The system further includes a hydraulic output configured to be fluidly coupled to a hydraulic braking system of a trailer, and a pneumatic output configured to be fluidly coupled to a pneumatic braking system of a trailer. The hydraulic output is fluidly coupled to the outlet of the hydraulic base valve, and the pneumatic output is fluidly coupled to the outlet of the pneumatic base valve.

Abstract: A method of detecting a leak in a hydraulic trailer brake circuit of a trailer includes providing a controller, a base valve, a first sensor, a second sensor, a control valve having a solenoid, a reduction valve, a hydraulic fluid supply, a first brake output, and a second brake output. The method also includes supplying a first pressure to an inlet of the base valve and outputting a second pressure from an outlet of the base valve to the first brake output. The first pressure is detected by the first sensor and the second pressure is detected by the second sensor, and the detected first and second pressures are communicated to the controller. The difference between the first and second pressures are compared to a threshold, and a leak is detected in the hydraulic trailer brake circuit if the difference satisfies the threshold.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A method of detecting a leak in an air trailer brake circuit of a trailer includes providing a controller, a base valve, a first sensor, a second sensor, a leak control valve having a solenoid, a pneumatic fluid supply, a first brake output, and a second brake output. The method further includes supplying a first pressure to an inlet of the base valve and outputting a second pressure from an outlet of the base valve. The first pressure is detected with the first sensor and the second pressure is detected with the second sensor. The method also includes communicating the detected first pressure and the second pressure to the controller, and comparing a difference between first pressure and the second pressure to a threshold. A leak is detected in the air trailer brake circuit if the difference satisfies the threshold.

Abstract: A braking system of a trailer and work machine includes a pressurized fluid supply, a hydraulic base valve fluidly coupled to the supply, and a pneumatic base valve fluidly coupled to the supply. A proportional control valve is also fluidly coupled to the supply, and it includes an outlet disposed in fluid communication with the inlets of the hydraulic base valve and the pneumatic base valve. The system further includes a hydraulic output configured to be fluidly coupled to a hydraulic braking system of a trailer, and a pneumatic output configured to be fluidly coupled to a pneumatic braking system of a trailer. The hydraulic output is fluidly coupled to the outlet of the hydraulic base valve, and the pneumatic output is fluidly coupled to the outlet of the pneumatic base valve.

Abstract: A brake control system is provided for a vehicle having steerable front wheels, left and right brake units for braking left and right rear wheels, and a single manually operated brake input device. A main brake valve has a supply port, a return port, an outlet and a valve spool for controlling communication therebetween. The valve spool is coupled to a brake input device. A normally open left turn valve controls communication between the outlet and the left brake unit. A normally open right turn valve controls communication between the outlet and the right brake unit. A normally open balance valve controls communication between the left and right brake units. The system includes a brake input device sensor, a turn angle sensor and a vehicle speed sensor. A control unit controls the left and right turn valves and the balance valve as a function of signals from the sensors.

Abstract: A brake control system is provided for a vehicle having steerable front wheels, left and right brake units for braking left and right rear wheels, and a single manually operated brake input device. A main brake valve has a supply port, a return port, an outlet and a valve spool for controlling communication therebetween. The valve spool is coupled to brake input device. A normally open left turn valve controls communication between the outlet and the left brake unit. A normally open right turn valve controls communication between the outlet and the right brake unit. A normally open balance valve controls communication between the left and right brake units. The system includes brake input device sensor, a turn angle sensor and a vehicle speed sensor. A control unit controls the left and right turn valves and the balance valve as a function of signals from the sensors.

Abstract: A vehicle hydraulic brake system includes left and right manually operated brake pedals, and left and right hydraulic brake units. A pedal lock is movable to a locking position wherein the left and right brake pedals operate in unison. Left and right brake valves are operatively coupled to the corresponding brake pedal. A solenoid operated normally closed balance valve is connected between the left and right brake units. Optional left and right solenoid operated normally open blocking valves may be connected the corresponding brake valve and the corresponding brake unit. The blocking valves and the balance valve are controlled by an ECU as a function of sensed vehicle speed and brake pedal operation.

Abstract: A vehicle hydraulic brake system includes left and right manually operated brake pedals, and left and right hydraulic brake units. A pedal lock is movable to a locking position wherein the left and right brake pedals operate in unison. Left and right brake valves are operatively coupled to the corresponding brake pedal. A solenoid operated normally closed balance valve is connected between the left and right brake units. Optional left and right solenoid operated normally open blocking valves may be connected the corresponding brake valve and the corresponding brake unit. The blocking valves and the balance valve are controlled by an ECU as a function of sensed vehicle speed and brake pedal operation.

Abstract: A vehicle brake system includes a pump, a sump, brake units and left and right manually operated brake valves. The brake system also includes, for each brake unit, a solenoid operated on-off valve having a first port connected to a pilot of one of the brake valves, a second port, a third port connected to one of the brake units, a solenoid and a spring which opposes the solenoid. The brake system also includes, for each brake unit, a solenoid operated proportional valve. Each proportional valve controls communication between the pump, the sump and the second port of a corresponding one of the on-off valves.

Abstract: A vehicle brake system includes a pump, a sump, brake units and left and right manually operated brake valves. The brake system also includes, for each brake unit, a solenoid operated on-off valve having a first port connected to a pilot of one of the brake valves, a second port, a third port connected to one of the brake units, a solenoid and a spring which opposes the solenoid. The brake system also includes, for each brake unit, a solenoid operated proportional valve. Each proportional valve controls communication between the pump, the sump and the second port of a corresponding one of the on-off valves.