Abstract: An apparatus for stabilizing a material handling vehicle which enables or disables a vehicle's suspension system. Pilot-to-open check valves are mounted on hydraulic cylinders secured between the axle and frame of the vehicle. In a first embodiment, a pneumatically actuated check valve is opened or closed to permit or prevent fluid communication between the hydraulic cylinders. The absence of pneumatic pressure in the pneumatic circuit causes the check valves to close, thereby locking the axle to the frame for stability. The presence of pneumatic pressure in the circuit opens the check valves to permit fluid communication between the cylinders. In an alternative embodiment, a second electro-hydraulic circuit is provided in place of the pneumatic circuit for opening and closing pilot-to-close check valves mounted on the hydraulic cylinders.

Abstract: An apparatus for stabilizing a material handling vehicle which enables or disables a vehicle's suspension system. Pilot-to-open check valves are mounted on hydraulic cylinders secured between the axle and frame of the vehicle. In a first embodiment, a pneumatically actuated check valve is opened or closed to permit or prevent fluid communication between the hydraulic cylinders. The absence of pneumatic pressure in the pneumatic circuit causes the check valves to close, thereby locking the axle to the frame for stability. The presence of pneumatic pressure in the circuit opens the check valves to permit fluid communication between the cylinders. In an alternative embodiment, a second electro-hydraulic circuit is provided in place of the pneumatic circuit for opening and closing pilot-to-close check valves mounted on the hydraulic cylinders.