US Patent 11399464 Windrower header floatation system having assisted downforce control

An agricultural machine includes a float cylinder interconnecting a header linkage system and a frame. A rod side accumulator is in fluid communication with a rod side fluid port of the float cylinder. A float control valve is selectively controllable between an open position allowing fluid communication between a pressure source and the rod side accumulator, and a closed position blocking fluid communication between the pressure source and the rod side accumulator. A downforce accumulator is in fluid communication with a piston side fluid port of the float cylinder. A downforce control valve is selectively controllable between an open position allowing fluid communication between the pressure source and the downforce accumulator, and a closed position blocking fluid communication between the pressure source and the downforce accumulator.