Apparatus for tempering glass

Claim 1

IN APPARATUS OF THE CHARACTER DESCRIBED, THE COMBINATION OF A HEATING FURNACE, A CHILLING APPARATUS BEYOND SAID HEATING FURNACE, MEANS FOR SUPPORTING A GLASS SHEET UNDERGOING THERMIC TREATMENT IN THE COURSE OF ITS TRAVEL INTO AND OUT OF SAID FURNACE AND INTO SAID CHILLING APPARATUS ADAPTED TO APPLY A CHILLING MEDIUM ONTO THE OPPOSITE FACES OF THE SHEET, A MOVABLE SCREEN FOR MASKING A PREDETERMINED PART OF THE GLASS SHEET COMPRISING A PLATE SPACED FROM AND PARALLEL TO THE SHEET, SAID PLATE BEING OF GREAT HEAT ABSORBING CAPACITY AND OF SUBSTANTIAL THICKNESS WITH THE THICKNESS AT ONE PORTION THEREOF BEING GREATER THAN THAT OF ANOTHER PORTION, AND SUPPORTING MEANS FOR SAID MOVABLE SCREEN ADAPTED TO MOVE SAID SCREEN FROM AN INOPERATIVE POSITION BEYOND THE BOUNDARIES OF THE GLASS SHEET INTO AN OPERATIVE POSITION LATERALLY OF THE SHEET TO MASK SAID PART THEREOF DURING AT LEAST THE CONCLUDING PERIOD OF THE HEAT TREATMENT OF SAID SHEET WITHIN THE HEATING FURNACE.