Method of manufacturing glass vacuum envelopes

A method of manufacturing vacuum casings or vacuum casing parts made of glass for electronic valves, particularly cathode ray tubes, in which a substantially plane glass plate is heated beyond the softening point and is deformed by means of an appropriately moulded stamp, characterised in that said glass plate is clamped at the circumference at least at several points;

• that the free part of said glass plate is heated;
• that when said glass plate begins to soften, said stamp is pressed against said glass plate perpendicular to the plane of extension of said glass plate;
• that said stamp is moved on in the pressing direction relative to said clamping points with further supply of heat at the same time, wherein the glass of said plate substantially abuts the end surface and the side surfaces of said stamp while at the same time the thickness of said glass becomes thinner;
• and that after at least partial cooling of the moulded glass body has taken place, and after removal of said stamp and release of the clamping points, at least the edge which has been formed by clamping is removed.