Abstract: A suspension system isolates the operator cab or seat from vibrations in the chassis of a vehicle. At least one hydraulic actuator is connected between the cab or seat and the vehicle chassis. An accumulator is coupled to the hydraulic actuator and acts as a hydraulic spring to attenuate high frequency vibrations. An electrically operable, three-position, closed-center control valve selectively connects the hydraulic actuator to a source of pressurized hydraulic fluid or a reservoir. Sensors detect acceleration and displacement of the cab or seat to which a controller responds by operating the valve. That control of the valve actively drives the hydraulic actuator to produce motion that counters the relatively low frequency vibrations from the chassis.

Abstract: A suspension system isolates the operator cab or seat from vibrations in the chassis of a vehicle. At least one hydraulic actuator is connected between the cab or seat and the vehicle chassis. An accumulator is coupled to the hydraulic actuator and acts as a hydraulic spring to attenuate high frequency vibrations. An electrically operable, three-position, closed-center control valve selectively connects the hydraulic actuator to a source of pressurized hydraulic fluid or a reservoir. Sensors detect acceleration and displacement of the cab or seat to which a controller responds by operating the valve. That control of the valve actively drives the hydraulic actuator to produce motion that counters the relatively low frequency vibrations from the chassis.

Abstract: An apparatus and method for controlling variation in the pitch of an agricultural vehicle, where the apparatus includes a controller that controls a position of an implement attached to the agricultural vehicle, and a first valve that is coupled to, and receives a first control signal from, the controller. The apparatus further includes a suspension cylinder having a first chamber that is hydraulically coupled to the first valve. The first control signal provided from the controller is functionally related to a first additional control signal provided by the controller, and the first additional control signal is used to determine the position of the implement.

Abstract: A vehicle suspension has one or more hydraulic cylinders connecting an axle to a frame of the vehicle and each cylinder has a first and second chambers. The suspension operates in either a regeneration mode, in which a fluid path is provided between the first and second chambers, and a double acting mode, in which the first and second chambers are isolated from each other and fluid flows between each chamber and a separate accumulator. The selection between the regeneration and double acting modes is made in response to the pressure level in the cylinder as determined by a pressure sensor of a closed loop control system or by the pressure versus current characteristics of a electrically operated valve in the suspension for a loop control system. The hydraulic system also is able to raise and lower the suspension as necessary due to changes in the load carried by the vehicle.

Abstract: An apparatus and method for controlling variation in the pitch of an agricultural vehicle are disclosed. The apparatus includes a controller that controls a position of an implement attached to the agricultural vehicle, and a first valve that is coupled to, and receives a first control signal from, the controller. The apparatus further includes a suspension cylinder having a first chamber that is hydraulically coupled to the first valve. The first control signal provided from the controller is functionally related to a first additional control signal provided by the controller, and the first additional control signal is used to determine the position of the implement.

Abstract: A vehicle suspension has one or more hydraulic cylinders connecting an axle to a frame of the vehicle and each cylinder has a first and second chambers. The suspension operates in either a regeneration mode, in which a fluid path is provided between the first and second chambers, and a double acting mode, in which the first and second chambers are isolated from each other and fluid flows between each chamber and a separate accumulator. The selection between the regeneration and double acting modes is made in response to the pressure level in the cylinder as determined by a pressure sensor of a closed loop control system or by the pressure versus current characteristics of a electrically operated valve in the suspension for a loop control system. The hydraulic system also is able to raise and lower the suspension as necessary due to changes in the load carried by the vehicle.

Abstract: A integrated assembly form a parallel arrangement of a relief valve, an orifice and a check valve. A body has a first flange with a perimeter surface that engages a wall of a bore in which the assembly fits. An number of apertures extend through the flange. A second flange extends from the body and has an annular lip which defines a recess cavity at one end of the body. The body has a passage extending between the other end and the recess. A check valve member is slidably mounted on the body and closes the aperture when pressure adjacent the second end is greater than pressure adjacent the first end. A plurality of disks are mounted on the body and engage the annular lip to form an orifice between the disks and the lip. The disks disengage the annular lip when pressure in the bore adjacent to the second end is greater than predefined level.