GB709865A - Improvements in and relating to the manufacture of decorative electric incandescent lamps - Google Patents

Abstract

709,865. Electric incandescent lamps. BRITISH THOMSON-HOUSTON CO., Ltd. June 30, 1952 [June 30, 1951], No. 16400/52. Class 39 (2) In making electric incandescent lamps of the kind having envelopes of irregular shape, e.g. in the shape of fruit, lanterns &c. bulbs which are of globular, tubular or pear shape have a lamp mount sealed within them in a lamp-making machine of the conventional type and are then heated to a pliable condition while a non-oxidizing gas is introduced at a pressure sufficient to prevent them from collapsing, after which substantially the entire body portions of the envelopes are reshaped prior to their being evacuated and tipped off or sealed. Reshaping is effected by positioning a two-part mould about a bulb and admitting a puff of non-oxidizing gas into the exhausting tube. Fig. 8 shows a bulb 28 that has been inverted after sealing a glass stem-type mount 22 and exhausting-tube 24 within it, the latter tube being held in a rubber chuck 12 of a conventional machine whereby a non-oxidizing gas at low-pressure is introduced while the exterior of the bulb is flooded with relatively soft gas flames 13. When softened the bulb is immediately enclosed in a two-part mould 15, Fig. 9, having a mould cavity 16 of the desired configuration, and a puff of non-oxidizing gas causes the glass to take the shape of the cavity. After hardening, the reshaped bulb is exhausted, sealed, and capped. A bulb of the butt-sealed type may be reshaped in a similar manner.