Fuel injection pump

Claim 1

IN A FUEL INJECTION PUMP, A HOUSING HAVING A BORE; A MULTI-STAGE PISTON ROTATABLY AND RECIPROCABLY RECEIVED IN SAID BORE, SAID PISTON HAVING INNER END AND AN OUTER END AND COMPRISING A FIRST STAGE OF SMALLER DIAMETER ADJACENT TO SAID INNER END, A SECOND STAGE OF LARGER DIAMETER ADJACENT TO AND DEFINING WITH SAID FIRST STAGE A SHOULDER, AND A THIRD STAGE OF MAXIMUM DIAMETER ADJACENT TO SAID OUTER END, A PORTION OF SAID BORE FORMING A CYLINDER CHAMBER FOR SAID THIRD STAGE AND SAID HOUSING FURTHER HAVING A SUCTION SPACE COMMUNICATING WITH SAID CYLINDER CHAMBER AND CHANNEL MEANS CONNECTING SAID CHAMBER WITH SAID SPACE; A SOURCE FOR FUEL CONNECTED WITH SAID SPACE; DRIVE MEANS INCLUDING A ROTARY SHAFT ADJACENT TO SAID OUTER END, A CAM AND FOLLOWER ASSEMBLY DRIVINGLY CONNECTING SAID SHAFT WITH THE OUTER END OF SAID PISTON, AND RESILIENT MEANS OPERATING BETWEEN SAID HOUSING AND SAID SHOULDER FOR BIASING SAID PISTON IN A DIRECTION TOWARD SAID SHAFT; AND FUEL QUANTITY REGULATING VALVE MEANS PROVIDED IN SAID CHANNEL MEANS FOR PERMITTING RETURN FLOW OF FUEL FROM SAID CYLINDER CHAMBER INTO SAID SPACE WHEN THE ROTATIONAL SPEED OF THE PISTON RISES TO A PREDETERMINED VALUE.