Abstract: Disclosed are techniques of heating and bending glass sheets by gravity, in particular for the production of laminated automobile glazings. In the techniques considered, the glass sheet is carried in a horizontal position by a carriage that brings it step by step into the cells of a furnace where it remains successively during its heating. According to the invention, the heat capacity of walls (26) of the cells has a value lower than that of carriage (18) and of the glass sheet. To heat all the glass sheets in the same way and to limit the reaction time of the furnace, the temperature of heating resistors (31) is regulated, and the weight of the carriage to be heated is limited. The latter can advantageously consist of two parts, one of which remains outside the furnace.

Abstract: Compression stresses are formed on the periphery of a glass sheet by blowing cooling air on the periphery of the heated glass sheet. The cooling air is blown by using a pyramidal deflector to deflect air flow radially outward toward the edges of the glass sheet. By adjusting the spacing between the deflector and the glass sheet, the size of a central, relatively quiescent, zone can be adjusted. The air flow is provided by a duct which can include a pyramidal skirt which surrounds the deflector to form a gas flow path whose size controls the cooling rate. Pyramidal flaps within the gas flow path can be used for adjusting cooling gas pressures.