Building construction

Claim 1

A MOLD FOR POURED CONCRETE CONSTRUCTION COMPRISING: A BASE, AN OPPOSED PAIR OF LONGITUDINAL APERTURED FORMS ATTACHED TO SAID BASE AND A PAIR OF END PLATES, COLLAPSIBLE OPEN CORE MOLDS INSERTED IN SAID APERTURES EACH HAVING A TOP PORTION AND A PAIR OF RESILIENT ARCUATE SIDE MEMBERS THE EDGES OF WHICH PROJECT INWARDLY, SIDE SPREADER MEANS IN SAID CORE MOLDS INCLUDING SUBSTANTIALLY FLAT RECTANGULAR PLATES PIVOTALLY ATTACHED TO THE TOP PORTION OF SAID CORE MOLDS AT EACH END THEREOF, SAID SPREADER MEANS HAVING DIVERGING FACES WHICH ENGAGE THE INNER PROJECTING EDGES OF SAID ARCUATE SIDE MEMBERS TO SPREAD THE SAME OUTWARDLY WHEN SAID SPREADER IS IN THE VERTICAL POSITION, THE CURVATURE OF SAID RESILIENT ARCUATE SIDE MEMBERS BEING SUCH AS TO ALLOW A SIMULTANEOUS DECREASE IN BOTH THE HORIZONTAL AND VERTICAL DIMENSIONS WHEN THE SPREADER IS MOVED TO THE HORIZONTAL POSITION SO THAT THE CORE MOLD IS EASILY EXTRACTED FROM OR INSERTED INTO THE SAID APERTURED FORMS, THE CURVATURE OF THE SAID SIDE PORTIONS CONSTITUTING AN ARC GREATER THAN A SEMICIRCLE WHEN IN THE EXPANDED POSITION AND THE INNER EDGE OF SAID SIDE PORTIONS HAVING A FLANGE TO RESTRICT THE SEEPAGE OF CONCRETE INTO THE INTERIOR OF THE CORE.