Pump for semi-fluid material

Claim 1

A CONCRETE PUMP COMPRISING: (A) A HOPPER FOR SUPPLYING CONCRETE TO BE PUMPED, SAID HOPPER HAVING A PAIR OF SUBSTANTIALLY CIRCULAR OUTLETS; (B) A PUMP CYLINDER IN FLUID COMMUNICATION WITH EACH OF SAID OUTLETS; (C) A CONCRETE DISCHARGE LINE IN FLUID COMMUNICATION WITH EACH PUMP CYLINDER, EACH OF SAID DISCHARGE LINE HAVING A SUBSTANTIALLY CIRCULAR UPSTREAM END MOUNTED ADJACENT ITS ASSOCIATED OUTLET AND DOWNSTREAM END DISCHARGING INTO A COMMON OUTLET CONDUIT; (D) A PISTON RECIPROCALLY MOUNTED IN EACH CYLINDER; (E) A PISTON ROD CONNECTED TO EACH PISTON, EACH PISTON ROD HAVING A JOURNAL AT ITS END REMOTE FROM SAID PISTON; (F) A HEMISPHERICALLY-SHAPED VALVE SWINGABLY MOUNTED BETWEEN EACH OF SAID OUTLETS AND THEIR ASSOCIATED UPSTREAM ENDS FOR SELECTIVE ENGAGEMENT WITH SAID OUTLETS AND SAID UPSTREAM ENDS OF SAID DISCHARGE LINE; (G) MEANS FOR SIMULTANEOUSLY SEATING ONE VALVE IN ITS ASSOCIATED OUTLET AND THE OTHER VALVE IN ITS ASSOCIATED UPSTREAM END; (H) A CRANK CONNECTED TO EACH VALVE FOR SWINGING EACH VALVE TO A SEATED POSITION; (I) A CONTROL BAR CONNECTED TO EACH CRANK, SAID CONTROL BAR EXTENDING OVER AN ENDLESS CHAIN; (J) MEANS FOR CONNECTING SAID ENDLESS CHAIN TO SAID CONTROL BAR CYCLICALLY TO SLIDE SAID CONTROL BAR AND ACTUATE SAID VALVES; (K) A PAIR OF ENDLESS CHAINS MOUNTED ASTRADDLE EACH PISTON ROD, AND (L) MEANS ROTATABLY MOUNTED IN EACH JOURNAL FOR CONNECTING SAID PISTON RODS TO SAID CHAINS WHEREBY SAID PISTON ARE RECIPROCATED THEREBY.