Horsepower summation control for variable displacement pumps

Abstract From the Canadian patent

Two variable displacement pumps each having a horsepower (or torque) control valve a pressure limiting valve and a displacement feedback valve are, interconnected to provide fluid flow paths from the high pressure zone of one pump to the low pressure zone of the other pump via the horsepower control valve and thedisplacement feedback valve of the respective pumps and vice versa. When one pump is utilizing less than one-half of the available engine torque as at deadhead operation or low displacement operation wherein its pressure limiting valve determines themaximum delivery pressure or wherein the pump is in standby operation its, displacement feedback valve will correspondingly increase …