Variable displacement pump

Claim 1

A VARIABLE-DISPLACEMENT METERING PUMP INCLUDING A HOLLOW BODY DEFINING AN OPERATING CHAMBER CONTAINING A LUBRICANT, A CENTRAL ROTARY POWER SHAFT, A PISTON DRIVING HEAD IN SAID CHAMBER FOR ROTATION BY SAID SHAFT, DRIVING MEANS MOVABLY MOUNTED WITH RESPECT TO SAID HEAD AND TRANSVERSELY DISPLACEABLE WITH RESPECT THERETO TO BE MOVED IN AN ORBITAL PATH OF VARYING RADIUS IN RESPONSE TO ROTATION OF SAID SHAFT, A PUMP PISTON HOUSING MOUNTED ON SAID BODY AND DEFINING AN OPEN ENDED PISTON BORE COMMUNICATING AT ITS INNER END WITH SAID OPERATING CHAMBER, A PUMP CASING MOUNTED ON SAID HOUSING AND DEFINING A PUMP CAVITY, A PISTON MOUNTED FOR RECIPROCATION IN SAID PISTON BORE AND HAVING A PUMPING HEAD EXTENDING INTO SAID PUMP CAVITY, MEANS FOR RECIPROCATING SAID PISTON COMMENSURATE WITH THE ORBITAL MOVEMENT OF SAID DRIVING MEANS AND RESPONSIVE TO THE RADIUS OF SUCH MOVEMENT, TOGETHER WITH MEANS TO TRANSVERSELY DISPLACE SAID HEAD DURING ROTATION OF SAID SHAFT, SAID PUMP PISTON HOUSING BEING COUNTERBOARD FROM ITS OUTER END INWARDLY FOR A DISTANCE AT LEAST AS GREAT AS THE MAXIMUM STROKE OF THE PISTON AND PROVIDING LUBRICATION CLEARANCE SPACE BETWEEN THE PISTON AND THE PUMP PISTON HOUSING, INTERCOMMUNICATING MEANS FOR CIRCULATING LUBRICANT FROM SAID OPERATING CHAMBER TO SAID PISTON AT SAID CLEARANCE SPACE AND THENCE BACK TO SAID OPERATING CHAMBER, AND SEALING MEANS ABOUT THE PUMPING HEAD OF THE PISTON AT THE JUNCTURE OF SAID PUMP PISTON HOUSING AND SAID PUMP CASING FOR SEALING THE PISTON AND THE PUMPING CHAMBER AGAINST THE ESCAPE OF LUBRICANT AND PUMPED FLUID ALONG THE PISTON.