Concrete pump assembly

Claim 1

A pump assembly for handling concrete comprising a housing, a pair of closely arranged passages disposed wholly within said housing and converging from one side to an intermediate portion within said housing, an outlet passage within said housing and leading from said intermediate portion with the axis thereof disposed between said converging passages and extending from the side of said housing opposite to said first-mentioned side, a pair of pump cylinders in closely spaced parallel relation on the outer side of said housing and communicating with the outer ends of said converging passages respectively, pistons reciprocable respectively in said cylinders for operating concomitantly in opposite directions, a pair of laterally disposed inlet passagEs arranged on opposite sides of and wholly within said housing and communicating directly with said intermediate portion for supplying concrete to said converging passages respectively, the inner ends of said lateral passages being juxtaposed to the inner end of said outlet passage and the inner ends of said converging passages, a pair of oscillatable pins mounted in said housing, one being arranged on each side of said outlet passage and disposed in parallel relation, a flap valve mounted on each pin for oscillating movement therewith, said flap valves being so arranged that in one position one valve closes the adjacent inlet passage and uncovers said outlet passage, thereby enabling the piston on that side of the housing to force concrete from the respective cylinder through said intermediate portion and out through said outlet passage, and at the same time enabling the other valve to uncover the inlet passage adjacent thereto, thereby enabling the piston on that side of the housing to draw or suck concrete through the adjacent inlet passage and into the respective cylinder, said last valve in such position closing off the passage of the said outlet passage, and means for oscillating said pins.