US Patent 7063167 Self leveling towed implement

An implement has a tongue used to tow the implement that can be raised or lowered with respect to the rest of the implement. The tongue is raised or lowered by a hydraulic cylinder. The raising and lowering ports of the cylinder are connected to two hydraulic accumulators to permit the tongue to flex up or down while the implement is towed through the field. These accumulators are disconnected from the cylinder when the wings of the implement are lifted and the implement is towed over the road to prevent the implement from oscillating backwards and forward about an axis defined by its wheels.