摘要 |
An implement frame supported by hydraulically controlled lift wheels includes accumulator structure which is selectively connectable by valve structure to the lift cylinder circuit to control flow between the cylinder and accumulator according to implement status. For transport, the valve structure is opened for absorption of shock loads as the lift wheels move over obstructions and surface irregularities. For working in the field, the valve structure is closed to provide stable lift and precise depth control functions. The valve structure can be operated manually or automatically in response to vertical frame movement. In one embodiment, proportional valves are connected to an implement control unit for active suspension control which varies with changing transport conditions. A similar accumulator structure is provided for the hitch weight transfer system. |