Impeller pump and vane pump assembly with clutch deactivation

A fuel pump assembly for a gas turbine engine comprising:

• a pump housing;
• a primary drive shaft mounted for rotation within the housing;
• an impeller mounted upon the drive shaft in driving connection therewith such that rotation of the primary drive shaft produces a corresponding rotation of the impeller;
• a rotor having a plurality of slots therein mounted in the housing in encircling coaxial relationship to the primary drive shaft;
• a plurality of radially movable vanes positioned in the slots;
• a cam member mounted in the housing for engaging the radially outer surfaces of the vanes during rotation of the rotor for producing radially inward and outward vane movements;
• a secondary drive shaft at least partially disposed between the primary drive shaft and the rotor in driving connection with the rotor such that rotation of the secondary drive shaft produces a corresponding rotation of the rotor;
• means to engage the secondary drive shaft to drivingly interconnect the impeller and the secondary drive shaft;
• spring means to bias the engaging means into contact with the secondary drive shaft;
• and
• means urged radially outwardly by centrifugal force to progressively counter the bias of the spring means as the primary shaft speed increases and allow disengagement of the engaging means from the secondary drive shaft at a predetermined speed of the primary drive shaft.