Vickers hydraulic valves was invented by an American, Harry Franklin Vickers (1898 - 1977).He was the real American inventor and also an industrialist. American Society of Mechanical Engineers recognized him as the "Father of Industrial Hydraulics". Vickers invented Vickers hydraulic pumps (Vickers hydraulic valves) through his mechanical ability in combination with electronic and engineering training.
In his early invention of Vickers hydraulic(Vickers hydraulic valves), he already implemented hydraulic power steering system. Vickers hydraulic Values and pumps were fundamental to the rapid growth of the hydraulic industry, including his most famous innovation, the balanced Vickers vane hydraulic pump(Vickers hydraulic valves).
Sources:
http://www.antiquefarming.com/vickers-hydraulics.html
