Method of manufacturing reinforced plastic foam in sheet form

Claim 1

IN A METHOD OF MAKING A UNITARY SINGLE SHEET OF FLEXIBLE POLYURETHANE FOAM HAVING A UNITARY AND CONTINUOUS CELLULAR STRUCTURE THROUGHOUT WHEREIN A LIQUID POLYURETHANE FOAMING MIXTURE IS CONTINUOUSLY PREPARED AND CHILLED BELOW ROOM TEMPERATURE TO A TEMPERATURE AT WHICH IT WILL NOT REACT TO DELAY FOAMING THEREOF, SPREADING THE CHILLED MIXTURE ONTO A MOVING FLEXIBLE CARRIER WEB, DIRECTING A MOVING FLEXIBLE COVERING WEB OVER THE FOAM MIXTURE TO POSITION THE MIXTURE BETWEEN THE CARRIER AND COVERING WEBS, FIXING A UNIFORM THICKNESS OF THE CHILLED FOAM MIXTURE BETWEEN THE CARRIER AND COVERING WEBS, RAISING THE TEMPERATURE OF THE FOAM MIXTURE TO REACT THE MIXTURE AND FORM A FOAM SHEET BETWEEN THE WEBS, DIRECTING THE WEBS WITH THE FOAM THEREBETWEEN INTO A PRELIMINARY HEAT-CURING ZONE, SEPARATING THE CARRIER AND COVERING WEBS FROM THE FOAM SHEET; AND DIRECTING THE FOAM SHEET TO A FINAL CURING OPERATION, THE IMPROVEMENT IN COMBINATION THEREWITH OF REINFORCING THE FOAM SHEET WITH A FLEXIBLE DISCONTINUOUS REINFORCING LAYER EMBEDDED WITHIN SAID FOAM SHEET AND EXTENDING SUBSTANTIALLY PARALLEL TO THE BROAD FACES THEREOF COMPRISING: (A) FEEDING A DISCONTINUOUS LAYER OF SPACED REINFORCING STRANDS INTO THE LIQUID FOAMING MIXTURE AT A FIRST POSITION WHERE IT IS STILL CHILLED AND BEFORE ANY FOAMING HAS OCCURRED, (B) CONTROLLING THE ANGLE OF ENTRY OF SAID REINFORCING MATERIAL INTO SAID CHILLED FOAM MIXTURE AT SAID FIRST POSITION IN RELATION TO ITS POSITION BETWEEN THE BROAD FACES OF THE SHEET TO DETERMINE ITS FINAL LOCATION BETWEEN THE BROAD FACES OF THE SHEET SO THAT DECREASING THE ANGLE RELATIVE TO ONE OF THE BROAD FACES AT THE FIRST POSITION FINALLY POSITIONS THE REINFORCING ANGLE CLOSER TO THAT FACE, (C) COMPRESSING THE CARRIER AND COVER WEBS TOWARD EACH OTHER AT THE FIRST POSITION TO SQUEEZE EXCESS MIXTURE FROM BETWEEN THE WEBS AND FORCE THE REMAINDER OF SAID MIXTURE FULLY THROUGH AND AROUND THE STRANDS OF SAID REINFORCING LAYER BEFORE FOAMING OF THE MIXTURE TO FILL THE INTERSTICES AND COAT THE STRANDS WITH SAID FOAMING MIXTURE AND THEREBY ENTIRELY ENCLOSE THE REINFORCING LAYER IN THE FOAMING MIXTURE, (D) FREEING THE WEBS FROM SAID SQUEEZING ACTION AT A SECOND POSITION TO ALLOW THE MIXTURE THEREBETWEEN TO FOAM, (E) MOVING THE WEBS, REINFORCING LAYER AND FOAM MIXTURE TOGETHER AT A CONSTANT RATE, AND (F) FOAMING SAID MIXTURE IN SITU INTO A UNITARY FOAMED SHEET INTEGRALLY ABOUT AND PENETRATING THE INTERSTICES BETWEEN THE REINFORCING STRANDS SO THAT IS POSSESSES SUBSTANTIALLY THE SAME PORE STRUCTURE WITHIN SUCH INTERSTICES AS ON THE OPPOSITE SIDES OF THE REINFORCING ELEMENTS.