Stripping system for concrete slab casting form

Claim 1

IN A SYSTEM FOR STRIPPING CASTING FORMS HAVING NORMALLY FLAT BOTTOMS, SAID SYSTEM HAVING CONTOUR PLATE MEANS TO DEFINE A CURVED SURFACE OVER WHICH A CASTING FORM BOTTOM IS ARCHED TO CONFORM TO SAID CURVED SURFACE AND POWER MEANS ARE PROVIDED FOR ARCHING THE CASTING FORM BOTTOM, THE IMPROVEMENT COMPRISING AIR DUCT MEANS HAVING A FREE AIR DISCHARGE END LYING GENERALLY IN THE CURVED SURFACE DEFINED BY THE CONTOUR PLATE MEANS, MEANS INCLUDING A CONNECTION BETWEEN SAID AIR DUCT MEANS AND A SOURCE OF COMPRESSED AIR AND NORMALLY PROVIDING SUBSTANTIAL AIR FLOW RESISTANCE TO SAID AIR DUCT MEANS, SAID FREE DUCT END BEING ADAPTED TO BE SUBSTANTIALLY CLOSED AS THE BOTTOM OF SAID CASTING FORM APPROACHES THE DESIRED ARCH STRIPPING SHAPE AND MEANS RESPONSIVE TO THE RISE IN THE AIR PRESSURE INCIDENT TO THE SUBSTANTIAL BLOCKAGE OF AIR DISCHARGE FROM THE NORMALLY FREE DUCT END FOR CONTROLLING THE POWER MEANS FOR ARCHING THE CASTING FORM BOTTOM.