GB976445A - Electric lamp - Google Patents

Abstract

976,445. Incandescent electric lamps. SYLVANIA ELECTRIC PRODUCTS Inc. May 7, 1963 [May 7, 1962], No. 18041/63. Heading H1F. In an electric lamp the envelope of which has at least one end flattened, an end cap is attached to the flattened end and carries means for making contact with an external circuit and a fuse is disposed in the end cap and electrically connected with the contact-making means and with a lead-in conductor extending through the flattened end. In the form shown, the lamp envelope 1 has a flattened end 4 in which is sealed a molybdenum ribbon 8 connected to the lead-in wire 6 to the filament and to a wire 10 extending a small distance outside the end 4. A ceramic end cap 12 is slotted to fit on to the end 4 and has an opening 15 with shoulders 16 against which a contact 18 is held by an inner ceramic cylinder 19. A nickel wire 21 consisting of two portions 22, 23 of different diameters butt-welded together connects the wire 10 to the outside edge of the contact 18, the cylinder 19 being slotted to allow passage of the wire, the thinner part of which acts as a fuse. Alternatively, the outer end of the wire may be silversoldered to the centre of the contact 18. The outer surface of the contact 18 may be concave to facilitate engagement with contact pump in the lamp holder. A fuse may be provided at each end of the lamp. The invention may be applied to discharge lamps or filament lamps and especially to tubular filament lamps having an addition of iodine to the filling of inert gas.