VACUUM MOLD FOR SHAPING GLASS SHEETS

摘要

In apparatus for shaping sheets of heat-softenable material, such as glass and plastics, an upper vacuum mold is provided with an apertured wall member of low expansion refractory material to engage a heat-softened sheet during a portion of its shaping. In order to improve its durability, metal clamping devices that cause high local stresses in the refractory wall member are not used to secure the refractory wall member to metal structural elements of the vacuum mold. The present invention comprises novel mold structure to support a lower apertured wall member of refractory material on an inverted metal box member without metal attachment devices that induce high local stresses.