Abstract: A brake system for a machine, where an operator brake valve is controllable by an operator input device and an automatic brake valve is controllable by a control system. A control valve is connected to a brake and the operator and automatic brake valves and operated by the control system between an operator brake configuration fluidly connecting the operator brake valve to the brake and an automatic brake configuration fluidly connecting the automatic brake valve to the brake in an operator braking mode, the control valve provides that the brake is controllable in response to an input to the operator input device. In an automatic braking mode the control valve provides that the brake is controllable in response to a control signal from the control system.

Abstract: A retarding control assembly for a brake valve may include a bleed line configured for arrangement between a spring chamber of a brake command assembly and a tank line. The bleed line may include a check valve configured to allow fluid flow from the spring chamber to the tank and a check valve bypass configured to allow fluid flow from the tank line to the spring chamber passed the check valve and defining a restricted pathway.

Abstract: Two cooling fans acting on different heat exchangers may be driven via parallel circuits from a variable displacement hydraulic pump. At least one of the circuits includes a two position valve operable by a control system to vary the flow resistance of the circuit to share the flow between the two fan motors responsive to the relative heat load on the heat exchangers. The pump displacement is controlled to provide a constant hydraulic output pressure irrespective of the operational state of the or each valve assembly.

Abstract: A steering system for an articulated truck. The articulated truck is formed of a tractor and a trailer and an articulation joint. The steering system includes a hydraulic cylinder, with a cylinder barrel and a piston. The steering system provides for changes in angle between the tractor and the trailer. The hydraulic cylinder includes a snubbing tube projecting into the cylinder barrel. A hydraulic fluid passage opens into the cylinder barrel within the snubbing tube. The snubbing tube includes a main slot and a plurality of channels each extending between an interior and an exterior of the snubbing tube. The plurality of channels have a cross sectional area smaller than a cross sectional area of the main slot. When the articulated truck is steered, the piston moves in the cylinder barrel and the snubbing tube dampens the movement to prevent forces generated by the piston damaging the articulated truck.

Abstract: A retarding control assembly for a brake valve may include a bleed line configured for arrangement between a spring chamber of a brake command assembly and a tank line. The bleed line may include a check valve configured to allow fluid flow from the spring chamber to the tank and a check valve bypass configured to allow fluid flow from the tank line to the spring chamber passed the check valve and defining a restricted pathway.

Abstract: A system for delivering fluid in a machine is provided. The system includes a pump, a first valve disposed downstream of the pump, a check valve disposed downstream of the first valve, at least one accumulator disposed downstream of the check valve, and an auxiliary system disposed upstream of the check valve. The system further includes a control unit configured to receive a signal indicative of a fluid demand from the auxiliary system. The control unit is also configured to selectively control the first valve in a first position to limit flow of the fluid from the pump to the auxiliary system, and in a second position to allow flow of the fluid from the pump to the auxiliary system based, at least in part, on the received signal. The check valve limits flow of a fluid from the at least one accumulator to the auxiliary system.

Abstract: A system for delivering fluid in a machine is provided. The system includes a pump, a first valve disposed downstream of the pump, a check valve disposed downstream of the first valve, at least one accumulator disposed downstream of the check valve, and an auxiliary system disposed upstream of the check valve. The system further includes a control unit configured to receive a signal indicative of a fluid demand from the auxiliary system. The control unit is also configured to selectively control the first valve in a first position to limit flow of the fluid from the pump to the auxiliary system, and in a second position to allow flow of the fluid from the pump to the auxiliary system based, at least in part, on the received signal. The check valve limits flow of a fluid from the at least one accumulator to the auxiliary system.

Abstract: A system and method for detecting a pre-charge pressure of a hydraulic braking system are disclosed. A controller receives pressure readings from a pressure sensor indicative of the pressure of a hydraulic brake accumulator or the lower pressure of more than one accumulator. In response to fluid being provided to the hydraulic accumulator, the controller determines a first rate of pressure change, a second rate of pressure change different than the first rate, and a transition pressure between the first and second rates. The controller determines an approximate pre-charge pressure of the hydraulic brake accumulator based on the transition pressure. A warning can be provided to the operator or another when the determined pre-charge pressure is lower than a reference pressure.

Abstract: A system and method for detecting a pre-charge pressure of a hydraulic braking system are disclosed. A controller receives pressure readings from a pressure sensor indicative of the pressure of a hydraulic brake accumulator or the lower pressure of more than one accumulator. In response to fluid being provided to the hydraulic accumulator, the controller determines a first rate of pressure change, a second rate of pressure change different than the first rate, and a transition pressure between the first and second rates. The controller determines an approximate pre-charge pressure of the hydraulic brake accumulator based on the transition pressure. A warning can be provided to the operator or another when the determined pre-charge pressure is lower than a reference pressure.