GB695231A - Flywheel magnetos - Google Patents

Abstract

695,231. Ignition magnetos. WICO ELECTRIC CO. March 13, 1951 [June 10, 1950], No. 5988/51. Class 35. A high-speed fly-wheel magneto has a rotating permanent magnet connecting two pole-shoes and a stator having three diverging legs integrally connected at their inner ends, the corresponding spacing and arcuate lengths of the surfaces of the shoes and of the outer ends of legs being such, that with a predetermined closure and opening of the primary coil once every revolution, pre-ignition is prevented. Fig. 2 shows a fly-wheel 1 carrying a permanent magnet 7 connecting two pole-shoes 8, 9, the adjacent tips of which are separated by a small distance. The stator has an armature with three diverging legs 16, 17, 18. The respective dimensions of the pole-shoes and of the ends of the three legs are: the arcuate length of the face 19 of the leg 16 is slightly greater than that between the adjacent tips 12, 13 of the shoes; the angular spacing between the adjacent tips of the legs 16, 17 is equal to that between the adjacent tips of the legs 16, 18 ; the angular distance between the leading and lagging tips of each pole-shoo is slightly greater than that between the adjacent tips of adjacent legs, and the surfaces of the outer legs 17, 18 are equal to one another but greater than that of the middle leg 16. Fig. 3 shows a supporting laminated member 29 on which are mounted the legs 16, 17, 18 and other stator parts. The plate 29 has a central hole 34 to accommodate a hub 5 in which the crank-shaft 2 rotates. The plate 29 is strengthened by having two ribs 39, Fig. 4 (not shown). The ignition coils are mounted on a tubular core 48 which is held securely in the central leg 16 by a spring 45. Fig. 12 shows a complete breaker unit carrying a detachable condenser 67 having a terminal 69 which is connected to a spring 76 which presses against the breaker lever 71. Figs. 13, 14 show the rotor positions for an early and a late time of closure of the breaker points respectively. Fig. 13 provides for a large factor of safety, but Fig. 14 gives adequate safety against pre-ignition. In Fig. 14 the leading tip 12 of the shoe 8 is no closer than 5 degrees to the leading tip 22 of the leg 16. The means for closing and opening the primary coil includes a reversible mounting for the breaker mechanism thereof. Specifications 491,110 and 627,172 are referred to.