Method of making shoe soles

Claim 1

IN THE MANUFACTURE OF SHOE COMPONENTS HAVING A PLANTAR PORTION AND AN UPSTANDING MARGINAL PORTION SURROUNDING THE PLANTAR PORTION, THE PROCESS COMPRISING: (A) PROVIDING A SHEET OF THERMOSPLASTIC SYNTHETIC POLYMER CAPABLE OF BEING RENDERED PLIABLE BY HEAT, CONFORMED WHILE HOT TO THE SHAPE OF A MOLD, AND PERMANENTLY SET TO THE CONFORMED SHAPE, (B) PROVIDING A VENTED MOLD HAVING A PLANTAR SURFACE CORRESPONDING SUBSTANTIALLY TO THE SIZE AND PERIPHERAL CONTOUR OF A LAST BOTTOM, AND HAVING SIDE WALLS EXTENDING SUBSTANTIALLY PERPENDICULARLY FROM THE PERIPHERAL MARGIN OF SAID PLANTAR SURFACE, SAID SIDE WALLS HAVING A HEIGHT SUBSTANTIALLY GREATER THAN THE THICKNESS OF SAID SHEET OF SYNTHETIC POLYMER, (C) HEATING THE SHEET OF SYNTHETIC POLYMER TO AN EXTENT SUFFICIENT TO RENDER IT PLIABLE AND EXTENDING THE SHEET ACROSS THGE PLANTAR SURFACE OF, AN THE VENT IN, SAID MOLD WITH THE EDGES OF THE SHEET EXTENDING BEYOND THE PERIPHERY OF SAID PLANTAR SURFACE AND OVERHANGING SAID SIDE WALLS FOR A SUBSTANTIAL DISTANCE, (D) APPLYING VACUUM ON THE MOLD-SIDE OF THE PLIABLE SHEET WHILE MAINTAINING ATMOSPHERIC PRESSURE ON THE REVERSE SIDE THEREOF TO DRAW THE PLIABLE SHEET INTO CONTIGUITY WITH THE PLANTAR SURFACE AND SIDE WALLS OF SAID MOLD, AND MAINTAINING SAID VACUUM UNTIL THE SHEET HAS LOST ITS PLIABILITY AND HAS SET INTO CONFORMITY WITH THE MOLD, (E) AND THEN TRIMMING AWAY ANY EXCESS OF THE SHEET OUTWARDLY OF THE PORTIONS THEREOF CONFORMED TO THE SIDE WALLS OF SAID MOLD.