Manufacture of plastic covered panels for use in building construction

Claim 1

IN THE MANUFACTURE OF PLASTIC COVERED PANELS FOR USE IN BUILDING CONSTRUCTION, THE PANEL BODIES THEREOF HAVING BEEN PREFABRICATED AND PROVIDED WITH PERFORATIONS THAT PRESENT AN ORNAMENTAL DESIGN, THE METHOD WHICH INCLUDES THE FOLLOWING STEPS: SEVERING A FIRST SHEET OF PREDETERMINED SIZE FROM A ROLL OF THERMOPLASTIC MATERIAL; DEPOSITING THE PANEL BODY ONTO A HORIZONTALLY DISPOSED PERFORATED PLATE RIGIDLY MOUNTED NEAR THE OPEN UPPER END OF A HOLLOW HOUSING WITH A WIRE SCREEN INTERPOSED BETWEEN SAID PANEL BODY AND SAID PERFORATED PLATE; SUSPENDING SAID FIRST SHEET ABOVE THE PANEL BODY IN PREDETERMINED SPACED RELATIONSHIP RELATIVELY TO A HEATING UNIT DISPOSED THERABOVE, WITH THE MARGINAL PORTIONS OF THE SHEET CLAMPED BETWEEN VERTICALLY MOVABLE CLAMPING FRAMES; DIRECTING HEAT RAYS FROM THE HEATING UNIT AGAINST THE SUSPENDED SHEET FOR A DETERMINED LENGTH OF TIME SUFFICIENT TO SOFTEN THE SHEET AND IMPART ELASTICITY THERETO; LOWERING THE THUS TREATED SHEET ONTO THE PANEL BODY, WITH THE HEATING UNIT TURNED OFF AND SUCTION SIMULTANEOUSLY APPLIED FROM BELOW, THE LOWERED SHEET COMBINING WITH THE THUS CLOSED UPPER END OF SAID HOUSING TO FORM A VACUUM CHAMBER ABOUT AND BELOW THE PANEL BODY; FURTHER LOWERING THE SHEET UNTIL THE CLAMPED MARGINAL PORTIONS THEREOF REACHES A PLANE APPROXIMATELY CO-PLANAR WITH THE UPPER END OF THE HOUSING, THE SUCTION BEING CONSTANTLY APPLIED WHEREBY TO DRAW THE SHEET MATERIAL INTO THE PERFORATIONS OF THE PANEL BODY, AGAINST THE TOP SURFACE THEREOF, AND AGAINST THE UPPER HALF OF THE PERIPHERAL EDGES OF THE PANEL BODY; SHUTTING OFF THE SUCTION; ELEVATING THE UPPER CLAMPING FRAME; REMOVING THE THUS PROCESSED PANEL BODY AND TRIMMING THEREFROM THE