Elektrische Gluehlampe und Verfahren zu ihrer Herstellung

1,140,119. Glass to glass or metal seals. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 25 Aug., 1966 [28 Aug., 1965], No. 38116/66. Heading C1M. [Also in Divisions C5 and H1] In making an electric incandescent lamp, the flanged end of an exhaust tube is shaped round the leading-in wires by heating and compressing the tube into an annular recess on a surface enclosing the wires, while the exhaust tube is kept open by inserting a mandrel, a filament is mounted between the wires, the lamp neck is placed over the tube, heated and pressed on to the tube while a stream of cleaning gas is blown through the needle, withdrawing the needle and pinching the foot to seal the exhaust tube. The leading-in wires 5, 6, Fig. 1, are supported in holes 4 in a recess in a table 1, a hollow needle 8 being also passed through a central hole in the table and a heated exhaust tube 3 is pressed into the recess. The needle is coated with a lubricant consisting of zirconium and magnesium oxide to prevent sticking. Support wires may also be sealed into the end of the exhaust tube if desired. The mount so formed is disposed on a plate and a bulb 15, Fig 7, slipped over the end, a hollow needle 16 being inserted in the exhaust tube and an inert gas, e.g. argon or nitrogen, is blown through this to expel the air while the bulb 15 is heated and sealed to the tube. Two forming pieces 19 are then arranged round the softened neck of the bulb and inert compressed gas is blown in through the needle to assist in shaping the bulb. For vacuum lamps, the bulb is then exhausted through the exhaust tube 3 and sealed off. For gas filled lamps, either the lamp is exhausted and filled with inert gas or a hollow needle of diameter smaller than the tube 3 is inserted and a flushing gas serving also as a filling gas is blown into the bulb displacing the air or other gas in the bulb. The bulb is finally provided with the usual metal cap. For lamps having a base of compressed glass without a metal cap, the pinching jaws for sealing and shaping the base have upper portions for shaping the bulb. For lamps in which the filament extends at right angles to the leading-in wires, thereby necessitating the use of a bulb with a wide neck, a dish like part to which the bulb neck is sealed, is provided on the exhaust tube.