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.

Abstract: A hydraulic circuit controls a doubling acting cylinder of a vehicle suspension to provide load leveling and shock absorption functions. A set of solenoid valves control the application of pressurized hydraulic fluid from a supply line to the cylinder and from the cylinder to a tank return line to raise and lower the vehicle for load leveling. The chambers of the cylinder are interconnected by a parallel arrangement of a check valve, orifice and a relief valve. Another parallel arrangement of a check valve, orifice and a relief valve couples the cylinder to an accumulator. These parallel arranged components enable the doubling acting cylinder to function as a passive shock absorber. A lock-out valve is provided in the preferred embodiment a to defeat the shock absorber operation and provide a very stiff suspension.

Abstract: A hydraulic circuit controls a doubling acting cylinder of a vehicle suspension to provide load leveling and shock absorption functions. A set of solenoid valves control the application of pressurized hydraulic fluid from a supply line to the cylinder and from the cylinder to a tank return line to raise and lower the vehicle for load leveling. The chambers of the cylinder are interconnected by a parallel arrangement of a check valve, orifice and a relief valve. Another parallel arrangement of a check valve, orifice and a relief valve couples the cylinder to an accumulator. These parallel arranged components enable the doubling acting cylinder to function as a passive shock absorber. A lock-out valve is provided in the preferred embodiment a to defeat the shock absorber operation and provide a very stiff suspension.