Shaping glass sheets by gravity sag bending followed by blow forming

摘要

This invention covers shaping glass sheets to complicated shape by first preliminarily shaping said sheets to a prebent shape while supported on an outline mold, then completing the shape while cradling the prebent sheets within a thin flexible blanket of fiber glass cloth during final shaping by blow forming. This invention also covers a technique of cradling glass sheets in a flexible fiber glass blanket that is wrapped over the margin of the glass sheets to be shaped by blow forming. The margin of the blanket is reversely wrapped over a frame-like ring that prevents the marginal edge from curling and maintains the cradle in tension against the lower major surface of the glass sheet during shaping by blow forming.