Patent ID: 8596991

Claim:
A multiple stage pump for delivering fuel to an engine, comprising: a) a pump housing; b) a boost stage operable at engine start to draw fuel into the pump housing at a boost stage pressure; c) a first pumping stage operable upon engine start for receiving fuel from the boost stage and delivering the fuel from the pump housing to a fuel metering unit, the first pumping stage having a driving start gear and a driven start gear, d) a second pumping stage operable upon engine start and during engine cruise operation for receiving fuel from the boost stage and delivering the fuel from the pump housing to said fuel metering unit, the second pumping stage having a driving cruise gear and a driven cruise gear, wherein the driving start gear of the first pumping stage is threadably connected to a journal of the driven cruise gear of the second pumping stage, and the driven start gear of the first pumping stage is piloted on a journal of the driving cruise gear of the second pumping stage; e) a main drive shaft operatively connected to the driving cruise gear; and f) a hydraulically actuated valve in fluid communication with the first and second pumping stages, and configured to control fuel flow through the first pumping stage when the boost stage pressure rises to a predetermined level.