Patent ID: 7165396

Claim:
A tandem pump assembly of the type including a housing defining a fluid inlet port and a fluid outlet port; a first pump disposed in said housing and driven by an input shaft, said first pump comprising a variable displacement, over-center pump, including first fluid pressure responsive means for varying the displacement of said first pump in response to the porting of a control pressure, said first pump having an inlet in fluid communication with said fluid inlet port, and an outlet in fluid communication with said fluid outlet port; a second pump disposed in said housing and driven by said input shaft, said second pump having an inlet in fluid communication with said fluid inlet port, and an outlet in fluid communication with said fluid outlet port; characterized by: (a) said tandem pump assembly including only one pressure override valve means associated with said fluid outlet port, and operable, in response to a fluid pressure at said fluid outlet port in excess of a pressure override setting, to communicate pressurized fluid to said first fluid pressure responsive means, in a manner tending to decrease the displacement of said first pump without effecting the displacement of said second pump, until said fluid pressure is substantially equal to said pressure override setting.