Method and machine for obtaining asymetric convex glass sheets

A method for producing bent glass sheets comprising:

• making glass sheets run over at least one shaping bed, for bending them, along a path with a curved profile in a run direction of the glass sheets, the glass sheets having been brought beforehand to their softening temperature, progressively giving them a desired bent shape;
• wherein, between an initial bending phase in which the glass sheets begin to adopt their shape and a final phase of bending, continuous blowing of air is performed, at a point on the path along which the glass sheets run, onto at least one face of the running glass sheets, under conditions capable of asymmetrically influencing a final concavity of the bent glass sheets by comparison with a concavity that the final bending would have given without the blowing.

Bent glass sheets exhibiting asymmetry likely to be detected by polariscopy or by measuring stress by using techniques employing an epibiascope.

A machine for bending glass sheets comprising:

• means for moving along glass sheets that have been raised beforehand to their softening point, giving them a desired bent shape;
• at least one nozzle for blowing air continuously, the at least one nozzle arranged at a point on a line along which the glass sheets run after the glass sheets have began to take shape and before a final phase of the bending, the at least one nozzle being arranged in such a way as to blow air asymmetrically onto the glass sheets, and set up so that the air blowing influences a final concavity of the bent glass sheets by comparison with a concavity that the final bending would have given without the blowing.