Constant delivery positive displacement pump

Claim 1

IN A CONSTANT DELIVERY PUMP COMPRISING A FRAME, A FIRST PISTON PUMP UNIT ON SAID FRAME INCLUDING A FIRST CYLINDER, A FIRST PISTON MOVABLE IN TH CYLINDER, AND A FIRST INTAKE AND A FIRST DISCHARGE PASSAGE OPENING TO ONE END OF THE CYLINDER, A SECOND PISTON PUMP UNIT ON SAID FRAME OF SMALLER DISPLACEMENT THAN SAID FIRST UNIT AND INCLUDING A SECOND CYLINDER, A SECOND PISTON MOVABLE IN THE CYLINDER, A SECOND INTAKE PASSAGE OPENING TO ONE END OF THE SECOND CYLINDER AND COMMUNICATING WITH SAID FIRST DISCHARGE PASSAGE, AND A SECOND DISCHARGE PASSAGE OPENING TO SAID ONE END OF THE SECOND CYLINDER, AND VALVE MEANS IN SAID FIRST INTAKE PASSAGE AND IN SAID COMMUNICATING PASSAGES FOR PERMITTING FLOW OF MATERIAL TO BE PUMPED INTO SAID FIRST CYLINDER THROUGH SAID FIRST INTAKE PASSAGE AND FROM SAID FIRST CYLINDER TO SECOND CYLINDER THROUGH SAID COMMUNICATING PASSAGES, AND BLOCKING FLOW OF SAID MATERIAL IN THE REVERSE DIRECTION THROUGH SAID FIRST INTAKE PASSAGE AND COMMUNICATING PASSAGES, A ROTARY DRIVING SHAFT ON SAID FRAME, A CONNECTION BETWEEN SAID SHAFT AND FIRST PISTON FOR RECIPROCATING THE LATTER IN ITS CYLINDER AS THE SHAFT ROTATES TO EFFECT AN INTERMITTENT PUMPING ACTION OF THE FIRST UNIT, SAID CONNECTION INCLUDING ADJUSTABLE MEANS FOR VARYING THE STROKE OF THE FIRST PISTON THE SECOND PISTON BEING MOVABLE IN ONE DIRECTION IN ITS CYLINDER BY THE PRESSURE DEVELOPED BY THE PUMPING ACTION OF TH FIRST UNIT, A ROTARY CAM SEPARATE FROM SAID CONNECTION, MEANS RELEASABLY CONNECTING SAID CAM TO SAID SHAFT FOR ROTATION BY THE LATTER, AND CAM FOLLOWER MEANS ENGAGING A LIMITED PORTION OF THE SURFACE OF SAID CAM AND OPERATIVELY CONNECTED TO THE SECOND PISTON FOR MOVING THE LATTER PISTON IN THE OPPOSITE DIRECTION IN ITS CYLINDER AND CONTROLLING THE MOVEMENT OF THE LATTER PISTON IN SAID ONE DIRECTION IN ITS CYLINDER AS THE SHAFT ROTATES, SAID CAM SURFACE HAVING AN IRREGULAR PROFILE FOR EFFECTING MOVEMENT OF SAID SECOND PISTON IN PREDETERMINED TIME RELATIONSHIP WITH RESPECT TO MOVEMENT OF THE FIRST PISTON, AND SAID CAM BEING REMOVABLE FROM SAID SHAFT FOR REPLACEMENT BY A CAM HAVING A CAM SURFACE OF DIFFERENT PROFILE MATCHING THE ADJUSTED STROKE OF THE FIRST PISTON.