GB632746A - Improvements in apparatus for sealing glass envelopes - Google Patents

Abstract

632,746. Making electric lamps. SYLVANIA ELECTRIC PRODUCTS, Inc. Aug. 8, 1947, No. 22081. Convention date, Aug. 26, 1946. [Class 39(ii)] [Also in Group XL (a)] A machine of known type for sealing the glass envelope of a valve or lamp to a glass header which carries the mount and exhausting tube, is provided with an adapter which surrounds the exhausting tube and shields it from the heat of a burner which directs a preliminary heating flame towards the junction of the tube and the flat wafer of the header, and means is provided for guiding the flame in the required manner. Fig. 1 shows a workholding head of a machine of conventional type with an upper chuck 10 for holding a shell or tube S, and a lower chuck 12 comprising inner and outer sleeves 22, 20 respectively and retractable jaws 16 which grip the exhausting tube T to support the header H. The co-operating jaws 10, 12 are rotated continuously while being indexed through successive work stations in known manner. The adapter consists of a heat-resistant metal tube 14 which encloses the upper end portion of the tube T, a conical boss or cap 26 secured by setscrews 28 at the upper end of the sleeve 20, and a frusto-conical ring 32 supported at a slight distance above the cap 26 by vertiqal rods 30, Fig. 3, in the latter. The conical surface of the cap 26 is inclined at a smaller angle than that of the ring 32, and between them they define a passage for the flame from a burner 34 which subjects the header to preliminary heating. After such heating at a succession of work stations the shell and header are sealed together by flames from a pair of laterally directed burners, and subsequently annealed by a less intense flame, after which cooling air is directed upwardly between the conical surfaces of the members 26, 32.