Method of mold temperature control

Claim 1

IN A PROCESS OF FORMING A MOLDED FLEXIBLE SKIN FROM A VINYL PLASTISOL IN A THIN-WALLED SHELL MOLD, THE INSIDE MOLD FACE OF WHICH HAS A DESIGN OF THE SURFACE OF THE ARTICLE TO BE PRODUCED AND THE WALLS OF SAID SHELL MOLD BEING SO THIN AS TO BE UNABLE TO RESIST ANY SUBSTANTIAL DIFFERENTIAL PRESSURE WITHOUT DISTORTION, THE IMPROVEMENT COMPRISING PLACING SAID SHELL MOLD ON A DISCHARGE PAN WITH SAID MOLD FACE FACING UPWARDLY AND WITH SAID MOLD BEING SO MOUNTED THEREON AS TO PERMIT THE FREE OVERFLOW OF ANY FLUID TRAPPED IN SAID DISCHARGE PAN, MAINTAINING THREE RESERVOIRS OF A LIQUID HEAT EXCHANGE MEDIUM, THE FIRST OF SAID RESERVOIRS BEING MAINTAINED AT A COOLING TEMPERATURE OF LESS THAN 125*F., THE SECOND AT A GELLING TEMPERATURE IN THE RANGE OF 225-300*F., AND THE THIRD AT A CURING TEMPERATURE IN THE RANGE OF 375-450*F., PREHEATING SAID SHELL MOLD TO SAID GELLING TEMPERATURE BY WITHDRAWING LIQUID HEAT EXCHANGE MEDIUM FROM SAID SECOND RESERVOIR AND SPRAYING THE SAME AGAINST THE UNDERSIDE OF SAID SHELL MOLD WHILE COLLECTING THE LIQUID SO SPRAYED IN SAID DISCHARGE PAN AND RETURNING THE SAME TO SAID SECOND RSERVOIR, APPLYING AND GELLING A LAYER OF HEAT GELABLE AND CURABLE VINYL PLASTISOL TO SAID SHELL MOLD WHILE MAINTAINING SAID SHELL MOLD AT SAID GELLING TEMPERATURE BY MEANS OF THE SPRAY, THEN HEATING SAID SHELL MOLD AND THE PLASTISOL THEREIN TO SAID CURING TEMPERATURE BY CEASING FLOW OF THE LIQUID HEAT EXCHANGE MEDIUM FROM SAID SECOND RESERVOIR AND WITHDRAWING LIQUID HEAT EXCHANGE MEDIUM FROM SAID THIRD RESERVOIR AND SPRAYING THE SAME AGAINST THE UNDERSIDE OF SAID SHELL MOLD WHILE COLLECTING THE LIQUID SO SPRAYED IN SAID DISCHARGE PAN AND RETURNING THE SAME TO SAID THIRD RESERVOIR, THERAFTER RAPIDLY COOLING SAID SHELL MOLD BY CEASING FLOW OF THE LIQUID HEAT EXCHANGE MEDIUM FROM SAID THIRD RESERVOIR AND WITHDRAWING LIQUID HEAT EXCHANGE MEDIUM FROM SAID FIRST RESERVOIR AND SPRAYING THE SAME AGAINST THE UNDERSIDE OF SAID SHELL MOLD WHILE COLLECTING THE LIQUID SO SPRAYED IN SAID DISCHARGE PAN AND RETURNING THE SAME TO SAID FIRST RESERVOIR, AND AFTER SAID SHELL MOLD HAS BEEN COOLED TO A TEMPERATURE OF LESS THAN 125*F. REMOVING SAID VINYL SKIN FROM SAID SHELL MOLD, THE PRESSURE ON THE MOLD FACE AND UNDERSIDE OF SAID SHELL MOLD BEING SUBSTANTIALLY ATMOSPHERIC THROUGH ALL STEPS OF THE PROCESS.