Apparatus for calendering thermoplastic sheets

Claim 1

IN APPARATUS FOR CONTINUOUSLY CALENDERING PLASTIC COMPOSITIONS INTO CONTINUOUS SHEETING COMPRISING A PAIR OF HEATED, PARALLEL-POSITIONED, CLOSELY-SPACED ROLLS, SAID ROLLS ADAPTED TO BE ROTATED IN OPPOSITE DIRECTIONS, A PAIR OF HORIZONTALLY ADJUSTABLE PLATES POSITIONED ADJACENT THE BITE OF THE ROLLS AND HAVING ARCUATE SECTIONS FITTED CLOSELY TO THE ADJACENT PERIPHERAL SURFACES OF THE ROLLS ADAPTED TO CONFINE THE PLASTIC COMPOSITIONS ABOUT TO BE CALENDERED BETWEEN THE PLATES ALONG THE HORIZONTAL AXES OF THE ROLLS, HEATING MEANS WITHIN THE RESPECTIVE PLATES ADAPTED TO MAINTAIN THE TEMPERATURE OF THE PLATES AT SUBSTANTIALLY THE TEMPERATURE OF THE ROLLS WHEREBY DEFECTS IN THE SHEETING DUE TO COOLING AT THE EDGES OF THE PLASTIC COMPOSITION BEING CONFINED BETWEEN THE PLATES ARE PREVENTED AND INSULATING MEANS ASSOCIATED WITH THE PLATES AND EXTENDING FROM THE PLATES TOWARD THE ROLLS ADAPTED TO PREVENT LOCALIZED HEATING OF ADJACENT ROLL SURFACES.