Patent ID: 8133337

Claim:
A method for making a concrete block comprising the steps of: (A) mixing cement, water and compressive material in first proportions; (B) conveying the mixture in step (A) to a molding machine; (C) pouring the mix conveyed in step (B) into a mold comprising a mold box having an open bottom with a movable plate positioned at the bottom of the mold box, and a mold core having a plurality of tension springs that position a top of the mold core at a top of the mold box when the plurality of tension springs are not under tension, the mold core defining a plurality of regions in the mold box that will not receive the mix; (D) vibrating the mix in the mold to form a partial block element that has a shape defined by the mold box and the mold core; and (E) moving the movable plate downward while pushing downward on the mold core to stretch the plurality of tension springs a first distance, the movable plate continuing a downward movement after the mold core has traveled the first distance until the partial block element is clear from the mold box.