Metering pump

Claim 1

A LIQUID METERING PUMP COMPRISING: A HOUSING; A CAM SHAFT VERTICALLY DISPOSED AND MOUNTED FOR ROTATION IN SAID HOUSING; A SINGLE CYLINDRICAL CAM HAVING A SINGLE ANNULAR PERIPHERAL CAM TRACK, SAID CAM BEING FIXED TO SAID CAM SHAFT FOR ROTATION THEREWITH; FIRST AND SECOND VERTICALLY-DISPOSED CROSSHEADS IN OPPOSED RADIAL POSITIONS RELATIVE TO SAID CAM SHAFT; A PLUNGER SECURED TO THE UPPER END OF EACH CROSSHEAD; A VALVE BODY FOR EACH PLUNGER, SAID VALVE BODY HAVING THEREIN AT LEAST ONE BALL CHECK VALVE IN WHICH THE BALL MOVES VERTICALLY TO SEAT; A CAM FOLLOWER SECURED TO EACH CROSSHEAD AND ADAPTED TO FOLLOW SAID CAM TRACK, SAID CAM TRACK HAVING SUCH CONTOUR THAT WHEN SAID CAM SHAFT IS DRIVEN ROTATIONALLY, SAID CAM FOLLOWERS, CROSSHEADS, AND PLUNGERS ARE DRIVEN UP AND DOWN IN A RECIPROCATING MOTION; AND DRIVE MEANS FOR DRIVING SAID CAM SHAFT, SAID CAM TRACK HAVING SUCH CONTOUR THAT DURING A PORTION OF THE CYCLE BOTH PLUNGERS ARE MOVING UPWARDLY ON THE DISCHARGE STROKE, WITH ONE OF SAID PLUNGERS NEARING THE END OF ITS DISCHARGE STROKE AND DECELERATING CYCLOIDALLY, AND THE OTHER OF SAID PLUNGERS JUST STARTING ITS DISCHARGE STROKE AND ACCELERATING CYCLOIDALLY.