| 摘要 |
908,421. Sealing exhaust tubes of electrir lamps. PATENT-TREUHAND-GESELLSCHAFT FUR ELEKTRISCHE GLUHLAM PEN. Feb. 14, 1961 [March 2, 1960], No. 5448/61. Class 39 (2). [Also in Groups II and XXIII] - A method of tipping off the exhaust tube of a sealed envelope especially for use in making miniature incandescent lamps or photo-flash bulbs having a gas filling at a pressure greater than atmospheric consists in heating the glass by means of metal pinching jaws to a temperature at which a slow deformation of the glass occurs and maintaining the pinch at this temperature until sealing is complete, the time from the beginning of heating to the attainment of the deformation temperature being not more than o third of the total heating time and the pinch being kept at the deformation temperature for at least 15 seconds. In the last phase, the heating of the jaws may be somewhat increased. In a turret machine for carrying out the method, the lamps are loaded, at station A, Fig. 2, on to the exhaust heads 3 of the machine, each of which is provided with a pair of pinching jaws 4 which close on the exhaust tube at station B where the exhausting begins, the jaws being heated from station B onwards by fixed gas flames 6. After the lamps are exhausted, the gas filling is introduced at station D, the intensity of heating being increased to compensate for cooling by the gas. Sealing is complete at station E and the heating is discontinued, the sealed lamps being unloaded at F. The pinching jaws 7, Fig. 4a, consist of steel alloy with cutting edges of chromium, tungsten, carbon and cobalt and are provided with bores 10 into which the heating flames 11 are directed. The bores may have a single inlet 12 with two outlet apertures 13, 14. |
