GB693119A - Improvements in or relating to v-shaped electric lamp, discharge tube and like filaments - Google Patents

Abstract

693,119. Making electric components. PHILIPS ELECTRICAL INDUSTRIES, Ltd. Sept. 12, 1950 [Sept. 15, 1949], No. 22418/50. Class 83 (ii). [Also in Group XI] In a method of making a V-shaped filament for an electric lamp, discharge tube, &c., a filament 20, Fig. 2, is cut to length and its ends 22 are brought together and secured to a common current supply member 7 while the intermediate portion of its length is unsupported. In a machine for carrying out the process the ends of a filament are held by clamps 4a, 5b, Fig. 1, mounted on a common pivot 5 and which are swung to bring the ends 22 of the filament together for insertion in the hooked end 10 of a current supply member 7. The filament is fed between the clamps 4a, 4b from a reel 1 by tongs 3 and severed to length by a knife 4c, the clamps being radially adjustable from the pivot 5 for filaments of differed lengths. The ends of the filament are bent over at the clamps to form hooked ends 22. The current supply strip 7 is fed from reel 6 and bent to form a hooked end 10 by a roller 9 co-operating with a mandrel 8. The strip is then moved sideways and the hooked end 10 is engaged over the filament ends 22 and closed by a die 11. While held by the clamp the filament loop may be stretched by a resilient pin (not shown), to form the loop to the desired shape. The clamps 4a, 4b are then opened and the filament withdrawn by the strip 7 which is finally cut to length by co-operating knives 14 and dropped on to a conveyer belt 13. The filament 20 may be coated with an electron-emitting substance which is broken off at the hooked end 22 during bending. The end of the V-shaped loop forms the second current supply point and the coating is removed at this point during the stretching of the loop. In a modification the clamps 4a, 4b may be slidably mounted for moving to. gether. Specification 672,514 is referred to.