Surface shaping of compressible cellular polymers with continuous rotary apparatus

Abstract

Apparatus and methods for cutting compressible cellular polymers such as polyurethane foam, are characterized by a first die roller and a pressure roller, wherein both rollers define raised portions separated by recesses or depressions, and the raised portions on the first die roller register with the recesses of the pressure roller at a nip formed between the rollers. Portions of the polymer material extruded into the spaces between the raised portions of the first die roller are cut away, such that the cut product conforms substantially to the surface geometry of the first die roller, and the depth of cut is greater than with prior rotary cutting methods.

1 . An apparatus for making a sheet or pad of a cellular polymer material having a three-dimensional shaped support surface with raised portions separated by depressions by pressing a slab of the cellular polymer material that has a planar surface into a nip formed between a die having a cylindrical die surface with raised die portions separated by die depressions and a pressure roller parallel to said die surface, turning at least one of said die and said pressure roller with a motor means, compressing some portions of the cellular polymer material against said raised die portions to a reduced thickness and extruding other portions of the cellular polymer material into said die depressions, and cutting away said other portions with a blade, characterized in that:
 the die has a length and a circumference, and the raised die portions are in multiple first rows along the length wherein each first row extends around the circumference of the die and comprises a plurality of discrete raised die portions and the raised die portions have face surfaces with an outer periphery defining a geometric shape, and wherein the each of the raised die portions also is in one of a multiple of second rows that extend along the length of the die, with each such second row containing three or more raised die portions, and   the pressure roller has a length and defines a plurality of recesses in its outer circumferential surface that are in multiple first rows and multiple second rows along the length, wherein each first row extends around the circumference of the pressure roller and comprises a plurality of discrete recesses, with each recess having a perimeter of identical or substantially identical shape and size to the outer periphery of a respective one of said raised die portions, wherein each recess also is in one of the multiple second rows that extend along the length of the pressure roller, with each such second row containing three or more recesses, wherein each recess substantially registers with the respective raised die portion at the nip so that the outer periphery of each face surface is in alignment with the perimeter of the respective recess with which it is substantially registered, and   wherein cutting away said other portions is with a blade positioned in a cutting plane substantially tangent to the cylindrical die surface.   
     
     
         2 . The apparatus of  claim 1 , wherein the blade is positioned in a cutting plane substantially tangent to the cylindrical die surface. 
     
     
         3 . The apparatus of  claim 1 , wherein each raised die portion of the die registers with but does not nest within a respective recess in the pressure roller. 
     
     
         4 . The apparatus of  claim 1 , wherein each raised die portion of the die registers with and nests within a respective recess in the pressure roller. 
     
     
         5 . An apparatus for making a sheet or pad of a cellular polymer material having a three-dimensional shaped support surface with raised portions separated by depressions, comprising:
 a die having a cylindrical die surface and a length and a circumference, and having raised die portions separated by die depressions, wherein the raised die portions are in multiple first rows along the length wherein each first row extends around the circumference of the die and comprises a plurality of discrete raised die portions and the raised die portions have face surfaces with an outer periphery defining a shape, and wherein the each of the raised die portions also is in one of a multiple of second rows that extend along the length of the die, with each such second row containing three or more raised die portions,   a pressure roller parallel to said die surface and spaced apart therefrom to form a nip between an outer circumferential surface of the pressure roller and the cylindrical die surface, said pressure roller having a length and defining a plurality of recesses in its outer circumferential surface that are in multiple first rows and multiple second rows along the length, wherein each first row extends around the circumference of the pressure roller and comprises a plurality of discrete recesses, with each recess having a perimeter of identical or substantially identical shape and size to the outer periphery of a respective one of said raised die portions, wherein each recess also is in one of the multiple second rows that extend along the length of the pressure roller, with each such second row containing three or more recesses, wherein each recess substantially registers with the respective raised die portion at the nip so that the outer periphery of each face surface is in alignment with the perimeter of the respective recess with which it is substantially registered, and   a cutting device positioned in a cutting plane substantially tangent to the cylindrical die surface and in or just beyond the nip for cutting away some or all of portions of said cellular material extruded into said die depressions when said pressure roller presses the slab against the die.   
     
     
         6 . The apparatus of  claim 5 , further comprising a motor to rotate either or both of the die and the pressure roller. 
     
     
         7 . The apparatus of  claim 5 , wherein each raised die portion of the die registers with but does not nest within a respective recess in the pressure roller. 
     
     
         8 . The apparatus of  claim 5 , wherein each raised die portion of the die registers with and nests within a respective recess in the pressure roller.