Concrete pumping apparatus

Claim 1

CONCRETE PUMPING APPARATUS AND CONTROL, COMPRISING: (A) A SOURCE OF FLUID PRESSURE; (B) PUMPING MEANS INCLUDING A PAIR OF PUMPING CYLINDER EACH HAVING A RECIPROCABLE PISTON THEREIN AND A COMMON INLET-OUTLET END, SAID PISTONS BEING MECHANICALLY INTERCONNECTED SO AS TO BE OPERATED IN REVERSE ORDER BY FLUID PRESSURE ACTUATING MEANS CONNECTED WITH SAID SOURCE; (C) A SUPPLY HOPPER FOR MATERIAL TO BE PUMPED HAVING A SUPPLY CONNECTION TO THE INLET-OUTLET END OF EACH OF SAID PUMPING CYLINDERS; (D) A DISCHARGE CONNECTION FROM THE INLET-OUTLET END OF EACH OF SAID PUMPING CYLINDERS; (E) FLUID PRESSURE ACTUATED GATING MEANS OPERABLE TO CONNECT SAID PUMPING CYLINDERS IN INVERSE RELATION AND EACH OF SAID CYLINDERS ALTERNATELY TO THE SUPPLY CONNECTION AND DISCHARGE CONNECTION; (F) MEANS FOR CYCLICALLY INTERDEPENDENTLY CONTROLLING THE ENERGIZATION OF SAID GATING MEANS AND SAID PUMPING MEANS SO THAT THE DISCHARGE FROM ONE CYLINDER MUST BE COMPLETED BEFORE STARTING THE DISCHARGE FROM THE OTHER OF SAID CYLINDERS; AND (G) OVERRIDING MANUAL CONTROL FOR SAID PUMPING MEANS FOR ENERGIZING SAID FLUID PRESSURE ACTUATING MEANS SO AS TO MOVE A SELECTED ONE OF SAID PISTONS TO A COMPLETELY DISCHARGEED CYLINDER POSITION.