Patent ID: 6196555
Filing Date: 2001-03-06
Classification: B60G

Abstract:
A suspension system for a vehicle, comprising:a first hydraulic circuit with a first hydraulic cylinder operatively coupleable to a first side of the vehicle, the first hydraulic circuit being selectively controllable to move the first side of the vehicle and having a first pressure-controlled counterbalance valve connected to the first hydraulic cylinder;a second hydraulic circuit with a second hydraulic cylinder operatively coupleable to a second side of the vehicle, the second hydraulic circuit being selectively controllable to move the second side of the vehicle and having a second pressure controlled-counterbalance valve connected to the second hydraulic cylinder; anda connection between the first hydraulic circuit and the second hydraulic circuit, the connection including a single three-position leveling valve;wherein the first and second hydraulic cylinders both rise when the leveling valve is in a first position and pressurized fluid is supplied through the leveling valve and each respective counterbalance valve to each respective hydraulic cylinder,wherein the first and second hydraulic cylinders both lower when the leveling valve is in a second position and pressurized fluid drains from each cylinder through each respective counterbalance valve and through the leveling valve, andwherein the first hydraulic circuit and the second hydraulic circuit are isolated from and operate independently of each other when the leveling valve is in a third position.