GB961761A - Method of producing electric incandescent lamps and lamps produced by this method - Google Patents

Abstract

961,761. Electric incandescent lamps. PATENT - TREUHAND - GES. - FUR ELEKTRISCHE GLUHLAMPEN. Nov. 2, 1962 [Nov. 3, 1961], No. 41552/62. Heading H1F. In producing electric lamps in which two lead-in wires are sealed into a glass bead so as to be a fixed distance apart, a filament being secured to the ends of the lead-in wires, an exhaust tube is fused to the bead on the side opposite to the filament leaving an aperture in the exhaust tube free adjacent the point of fusion and the free ends of the lead-in wires extending along the tube, the assembly is introduced into the lamp envelope and the envelope and exhaust tube are sealed together, preferably by pinching, whereby the lead-in wires are also sealed in, the exhaust passage being held open by suitable known means during sealing. The exhaust tube may be kept open during fusion to the bead by blowing air through it. The end of the tube 3 may be chamfered and the bead 2 sealed to the resulting pointed end. The ends 10 of the lead-in wires may be looped back so as to be embedded in the pinch 8 leaving loops 11 which are subsequently bent back so that their ends lie in grooves 9 in the pinch, providing contacts for use with a suitable lamp socket. In place of using pinching jaws, the envelope may be held with its open end uppermost, the filament and exhaust tube assembly held in place and the edge of the envelope heated to cause it to collapse on to the exhaust tube, which is kept open by blowing air through it, by inserting a pin or by applying to the interior of the tube a coating having a higher softening temperature than the material of the tube.