GB172957A - Improvements in magneto-electric ignition apparatus - Google Patents

Abstract

172,957. Bosch Akt.-Ges., R. Dec. 13, 1920, [Convention date]. Magneto-electric machines.-The magnets and pole-shoes of an ignition magneto, in which the length of the armature is greater than the diameter, are formed as hollow cylinders or parts of cylinders, and the magnets lie completely enshrouded within the outer surface of a cylinder of which the pole-shoes form almost the whole or part. Fig. 1 shows magnets 3 and pole-shoes 1 forming a complete cylinder inserted in a casing 2. In Figs. 2 and 3 the magnets 3 and armature 8 are enclosed by the pole-ring 1. In this case the magnets are inserted in the space surrounding the bearing; any number mav be used and, if necessary, at both ends of the armature. In the construction shown in Fig. 5, the annular magnet 3 rotates with the armature 8 so that four flux line changes are produced per revolution. Fixed contacts co-operating with a brush on the rotating armature convey current to the sparking plugs. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following subject-matter. The permanent magnets are constructed of steel of such high coercive force that the total length placed around the pole-shoe bore is at most equal to half the periphery of this bore; the pole-shoes may be of annular or other form. The magnet 3, Fig. 1 (Cancelled) consisting of a cylindrical bar with a V-shaped groove cut therein, is mounted so that the arms bridge across opposite pole-shoes 1 : pressure is applied by the spring-cover 5. Fig. 2 (Cancelled) shows a modified form. In Fig. 4 (Cancelled) the magnet 3 forms the base of the magneto. In another construction the casing is in one piece; the magnet and pole-shoes are introduced from the end, and a flat spring inserted between the magnet and casing ensures proper contact with the pole-shoes. Several magnets of smaller dimensions may be used. This subjectmatter does not appear in the Specification as accepted.