Laminating process and apparatus

Claim 1

A CONTINUOUS MULTISTAGE PROCESS FOR LAMINATING AN ASSEMBLY COMPOSED OF A PAIR OF MATCHED GLASS SHEETS AND A THERMOPLASTIC INTERLAYER COMPRISING ENCLOSING THE PERIPHERY OF THE ASSEMBLY WITH AN ENDLESS GROOVED EVACUATION RING THAT HAS THE GROOVE THEREOF EXTENDING LENGTHWISE OF AND IN OPEN COMMUNICATION WITH THE END EDGE OF THE ASSEMBLY, PLACING SAID RINGED ASSEMBLY IN A CLOSED CONTAINER, AS THE FIRST STAGE CONNECTING SAID EVACUATING RING TO AN EVACUATION SOURCE AND WITHDRAWING AIR SO AS TO REDUCE THE PRESSURE ABOUT THE PERIPHERY OF SAID ASSEMBLY TO LESS THAN ATMOSPHERIC, PRESSURING THE FLUID MEDIUM WITHIN SAID CONTAINER TO A FIRST RELATIVELY LOW PRESSUURE HEAD, AND APPLYING HEAT TO THE FLUID MEDIUM WITHIN SAID CONTAINER FOR A PREDETERMINED TIME TO HEAT SAID FLUID MEDIUM TO A FIRST PREDETERMINED TEMPERATURE SUFFICIENT TO CREATE A BOND BETWEEN SAID INTERLAYER AND SAID GLASS SHEETS, THEN AS THE SECOND STAGE DISCONTINUING THE EVACUATION AT THE END EDGES OF THE RINGED ASSEMBLY, INCREASING THE PRESSURE OF THE FLUID MEDIUM IN THE CONTAINER TO A SECOND RELATIVELY HIGH VALUE, AND AT THE SAME TIME INCREASING THE TEMPERATURE OF THE FLUID MEDIUM IN THE CONTAINER TO A SECOND TEMPERATURE SUFFICIENT TO CURE THE BOND BETWEEN THE GLASS SHEETS AND THE THERMOPLASTIC INTERLAYER, AND AS THE THIRD STAGE RELIEVING THE PRESSURE HEAD IN SAID CONTAINER AND DISCONTINUING THE HEATING OF THE FLUID MEDIUM IN THE CONTAINER.