GB1462296A - Spark wheels method of manufacturing spark wheels and dies for use therein - Google Patents

Abstract

1462296 Making spark wheels; rolling S P CHERNOCK 2 Aug 1974 [7 Jan 1974] 34203/74 Headings B3A and B3M [Also in Division F4] A spark wheel 20 (Fig. 1) for a cigarette lighter is initially provided on its surface with a number of grooves at an acute angle to the sides of the wheel, and then with composite raised cutting teeth which extend non-uniformly across the lands defined by the grooves. The teeth are formed by rolling dies 36 and 38 (Fig. 5) one or both of which are reciprocable, or between cylindrical dies. The teeth 46 of die 38 initially form teeth 26 on the wheel blank, the teeth having burrs 28 extending from their tips; the teeth 26 are then further deformed to provide composite teeth by the teeth of die 36. The teeth 46 on the dies are skewed, and each has a forming surface 50 and a sloping surface 52, with (optionally) a groove at the lower intersection of the surfaces. The surface 50 is inclined at between 0 and 12 degrees to a perpendicular to the die surface. The orientation of the teeth formed by the two dies differ. The dies may each have between 20 and 60 burr-forming teeth per inch. The formation of the grooves may be effected by a rolling die having suitable projections on its surface, by a screw machine, or by composite dies having an initial grooving section and a final tooth-forming section. The initial cylindrical blanks may be produced in stamping or heading presses or screw machines, and are hardened following the tooth formation.