Tandem pump assembly

Claim 1

In combination, an engine having an oil pan containing oil at a certain level, a tandem pump arrangement mounted in said oil pan, said pump arrangement comprising an oil pump for delivering the oil under pressure to lubricate the engine and a vacuum pump for establishing a vacuum, said oil pump having two meshing gears of different pitch diameter adapted to produce oil pumping action by their meshing engagement upon drive to the one gear having the larger pitch diameter and the drive thereby of the other gear having the smaller pitch diameter at a higher speed, drive means for connecting the engine to drive said one gear, said vacuum pump having an input connected to be driven by said other gear whereby said vacuum pump is driven through said oil pump at increased speed with an overdrive ratio determined by the ratio of the pitch diameters of said gears, said vacuum pump being lubricated by the oil in the oil pan and having an exhaust line exiting in the oil pan above said oil level so as to ensure return of such oil to the oil pan.