Abstract: A valve is provided including a first valve member and a second valve member. The first valve member includes a first step and a first orifice adjacent the first step. The second valve member includes a second step and a second orifice adjacent the second step. The second valve member is movable relative to the first valve member between an open position, in which the first orifice is fluidly connected the second orifice, and a closed position, in which the first orifice is substantially fluidly disconnected from the second orifice. The first and second steps are fluidly connected to the second orifice and substantially fluidly disconnected from the first orifice when the second valve member is in the closed position, and the first and second steps are fluidly connected to the first and second orifices when the second valve member is in the open position.

Abstract: An exemplary hydraulic system includes a plurality of digital valves, each valve fluidly connectable to a corresponding hydraulic load. The digitals valves are operable to fluidly connect the corresponding hydraulic load to a pressure source. The hydraulic system further includes a digital controller operably connected to the plurality of digital valves. The digital controller is configured to assign a priority level so that it is associated with each of a plurality of hydraulic loads, and to formulate a pulse width modulated control signal based on the assigned priority levels. The digital controller transmits the control signal to the plurality of digital valves for controlling the operation of the valves.

Abstract: Disclosed is an exemplary valve having a first valve member that may include at least one orifice, and which is moveable between a first position and a second position, and a second valve member that includes at least one orifice, and which is moveable relative to the first valve member between a first position, in which the at least one orifice of the second valve member is fluidly disconnected from the at least one orifice of the first valve member, and a second position, in which the at least one orifice of the second valve member is fluidly connected to the at least one orifice of the first valve member. The exemplary valve may also include first and second actuators for moving the first and second valve members between their respective first and second positions.

Abstract: An exemplary hydraulic system includes a plurality of digital valves, each valve fluidly connectable to a corresponding hydraulic load. The digitals valves are operable to fluidly connect the corresponding hydraulic load to a pressure source. The hydraulic system further includes a digital controller operably connected to the plurality of digital valves. The digital controller is configured to assign a priority level so that it is associated with each of a plurality of hydraulic loads, and to formulate a pulse width modulated control signal based on the assigned priority levels. The digital controller transmits the control signal to the plurality of digital valves for controlling the operation of the valves.

Abstract: A valve is provided including a first valve member and a second valve member. The first valve member includes a first step and a first orifice adjacent the first step. The second valve member includes a second step and a second orifice adjacent the second step. The second valve member is movable relative to the first valve member between an open position, in which the first orifice is fluidly connected the second orifice, and a closed position, in which the first orifice is substantially fluidly disconnected from the second orifice. The first and second steps are fluidly connected to the second orifice and substantially fluidly disconnected from the first orifice when the second valve member is in the closed position, and the first and second steps are fluidly connected to the first and second orifices when the second valve member is in the open position.

Abstract: In one embodiment, a hydraulic circuit has an input shaft, at least one positive displacement hydraulic pump, a plurality of positive displacement hydraulic motors, and at least one fluid line operatively connecting the at least one positive displacement hydraulic pump to the positive displacement hydraulic motors. In operation, the at least one positive displacement hydraulic pump is placed in an operative condition. At least one of the positive displacement hydraulic motors is also placed in an operative condition. A flow rate of fluid in the fluid line is measured, and the remaining positive displacement hydraulic motors are switched between an operative condition and a bypass condition according to the measured flow rate of the fluid.

Abstract: An exemplary hydraulic system includes a digital valve operable to fluidly connect a hydraulic load to a pressure supply, and an orifice disposed in a flow path between the hydraulic load and the digital valve. A digital controller is operably connected to the digital valve. The digital controller stores a target pressure drop across the orifice and is configured to determine an actual pressure drop across the orifice and formulate a control signal based on the target pressure drop and the actual pressure drop. The controller transmits the control signal to the digital valve for controlling the operation of the valve.

Abstract: An exemplary hydraulic system includes a plurality of digital valves, each valve fluidly connectable to a corresponding hydraulic load. The digitals valves are operable to fluidly connect the corresponding hydraulic load to a pressure source. The hydraulic system further includes a digital controller operably connected to the plurality of digital valves. The digital controller is configured to assign a priority level so that it is associated with each of a plurality of hydraulic loads, and to formulate a pulse width modulated control signal based on the assigned priority levels. The digital controller transmits the control signal to the plurality of digital valves for controlling the operation of the valves.

Abstract: A valve is provided including a first valve member and a second valve member. The first valve member includes a first step and a first orifice adjacent the first step. The second valve member includes a second step and a second orifice adjacent the second step. The second valve member is movable relative to the first valve member between an open position, in which the first orifice is fluidly connected the second orifice, and a closed position, in which the first orifice is substantially fluidly disconnected from the second orifice. The first and second steps are fluidly connected to the second orifice and substantially fluidly disconnected from the first orifice when the second valve member is in the closed position, and the first and second steps are fluidly connected to the first and second orifices when the second valve member is in the open position.

Abstract: An exemplary hydraulic system includes a digital valve operable to fluidly connect a hydraulic load to a pressure supply. A digital controller is operably connected to the digital valve. The digital controller stores a target value of a hydraulic system operating parameter and is configured to formulate a pulse width modulated control signal based on the target value. The digital controller transmits the control signal to the digital valve for controlling the operation of the valve.

Abstract: An exemplary hydraulic system includes a first digital valve fluidly connectable to a first hydraulic load and a pump. The first valve is operable to fluidly connect the first hydraulic load to the pump. A second digital valve is fluidly connectable to a second hydraulic load and the pump. The second valve is operable to fluidly connect the second hydraulic load to the pump. The system includes a first sensor for detecting a pump discharge pressure and a second sensor for detecting an inlet pressure of the first hydraulic load. A controller is configured to determine a time delay based on the pump discharge pressure and the first hydraulic load inlet pressure and to send a control signal instructing the second valve to commence opening at a time substantially equal to the time delay after commencing closing the first valve.

Abstract: Disclosed is an exemplary valve having a first valve member that may include at least one orifice, and which is moveable between a first position and a second position, and a second valve member that includes at least one orifice, and which is moveable relative to the first valve member between a first position, in which the at least one orifice of the second valve member is fluidly disconnected from the at least one orifice of the first valve member, and a second position, in which the at least one orifice of the second valve member is fluidly connected to the at least one orifice of the first valve member. The exemplary valve may also include first and second actuators for moving the first and second valve members between their respective first and second positions.

Abstract: In one embodiment, a hydraulic circuit has an input shaft, at least one positive displacement hydraulic pump, a plurality of positive displacement hydraulic motors, and at least one fluid line operatively connecting the at least one positive displacement hydraulic pump to the positive displacement hydraulic motors. In operation, the at least one positive displacement hydraulic pump is placed in an operative condition. At least one of the positive displacement hydraulic motors is also placed in an operative condition. A flow rate of fluid in the fluid line is measured, and the remaining positive displacement hydraulic motors are switched between an operative condition and a bypass condition according to the measured flow rate of the fluid.

Abstract: An exemplary hydraulic system includes a digital valve operable to fluidly connect a hydraulic load to a pressure supply, and an orifice disposed in a flow path between the hydraulic load and the digital valve. A digital controller is operably connected to the digital valve. The digital controller stores a target pressure drop across the orifice and is configured to determine an actual pressure drop across the orifice and formulate a control signal based on the target pressure drop and the actual pressure drop. The controller transmits the control signal to the digital valve for controlling the operation of the valve.

Abstract: An exemplary hydraulic system includes a digital valve operable to fluidly connect a hydraulic load to a pressure supply. A digital controller is operably connected to the digital valve. The digital controller stores a target value of a hydraulic system operating parameter and is configured to formulate a pulse width modulated control signal based on the target value. The digital controller transmits the control signal to the digital valve for controlling the operation of the valve.

Abstract: An exemplary hydraulic system includes a first digital valve fluidly connectable to a first hydraulic load and a pump. The first valve is operable to fluidly connect the first hydraulic load to the pump. A second digital valve is fluidly connectable to a second hydraulic load and the pump. The second valve is operable to fluidly connect the second hydraulic load to the pump. The system includes a first sensor for detecting a pump discharge pressure and a second sensor for detecting an inlet pressure of the first hydraulic load. A controller is configured to determine a time delay based on the pump discharge pressure and the first hydraulic load inlet pressure and to send a control signal instructing the second valve to commence opening at a time substantially equal to the time delay after commencing closing the first valve.

Abstract: An exemplary hydraulic system includes a plurality of digital valves, each valve fluidly connectable to a corresponding hydraulic load. The digitals valves are operable to fluidly connect the corresponding hydraulic load to a pressure source. The hydraulic system further includes a digital controller operably connected to the plurality of digital valves. The digital controller is configured to assign a priority level so that it is associated with each of a plurality of hydraulic loads, and to formulate a pulse width modulated control signal based on the assigned priority levels. The digital controller transmits the control signal to the plurality of digital valves for controlling the operation of the valves.

Abstract: A method of establishing a target pressure for a vehicle tire for storage in a receiver having a microcontroller where a sensor/transmitter combination is mounted on each wheel. After each tire is inflated to the target pressure the sensor/transmitters are sequentially triggered to send an identification code and a target pressure signal to the receiver for storage in memory. In an alternate embodiment, the target tire pressures are statistically averaged and a warning signal is generated if a single tire target pressure deviates a predetermined amount from the statistical average.

Abstract: An apparatus (10) allows atmospheric pressure into an environmentally sealed enclosure for creating an equilibrium that allows a sensor (28) make a proper measurement. A slot or opening (26) in the cover (14) exposes outside atmospheric air to a restricted portion of a gas permeable membrane (18). The membrane (18) allows a selected gas to pass through the membrane (18) creating the equilibrium in the housing (12). A gasket (16) positioned between the cover (14) and housing (12) seals the housing in an air tight manner except for the gases allowed in through the membrane (18). Pressure sensor (28) can then make a more accurate measurement. Apparatus (10) finds particular utility in a low pressure tire management system.

Abstract: A brake actuator having a switch device mounted to an actuator housing with a spring member partially surrounding an actuator rod and adapted to contact a large diameter section of the actuator rod when brake wear causes the actuator rod to travel to a service limit position. In normal operation the spring member is separated from a small diameter section of the actuator rod. The switch device is mounted to a first end of the spring member having first and second electrical contacts which extend and electrically contact a conduction plate attached to a second end of the spring member as long as the brake actuator rod has not traveled to the service limit.