Pressing glass objects, esp. the stem and foot of goblets - where remainder of gob left outside the mould is sheared off by knife mounted on pivot

摘要

Gob of glass is pressed into a mould so that part of the gob remains outside the mould cavity and is immediately sheared off while still in a plastic state. Pref. moulds have a base provided with an inlet hole for the gob; and a spherical recess is provided in the outer surface of the base. In the spherical recess is a shear knife mounted on a pivot and contg. a hole via which the gob can enter the mould. The knife is then driven on its pivot to shear off the portion of the gob left outside the mould. The mould base is pref. made of a Ni-Be alloy; and the shear knife pref. has a coating of a Cr-Ni alloy on its working surfaces. Used in fully automatic mfr., esp. of monolithic feet and stems for goblets.