GB882682A - High speed electromagnetic switching device - Google Patents

Abstract

882,682. Electromagnetic interrupters; contact members for switches. BRISTOL CO. Nov. 20, 1958 [Nov. 22, 1957], No. 37351/58. Class 38 (5). A synchronous interrupter or " chopper " has two magnetic members defining two gaps with one end of an angularly-movable armature in one gap and the other end adjacent to but outside the other gap. Fig. 1 shows an exploded view of parts which are clamped on two insulated bolts 11, 12 and include the magnetic members 14, 15 on non-magnetic cross-arms 16, 17. A U-shaped non-magnetic frame 18 with forked ends is shown in two parts between the ends of which fixed contact assemblies 27 . . . 30 and armature tabs 52, 53 are clamped with suitable spacers 19 . . . 26 and insulation 31 . . . 38 on each side of the contact assemblies. The armature 13 is T-shaped and is formed of two identical sheets of iron with a thin sheet of resilient material such as nickel-iron sandwiched between them with the tabs 52, 53, projecting to form resilient hinges. The stem 50 of the armature passes loosely through a coil 60 which rests on the stacked components between the members 14, 15 and is surrounded and shielded by permanent magnets 61, 62 arranged with like poles adjacent the members 14, 15. Moving contacts 54, 55 are insulated from the armature and connections 58, 59 therefrom are held between studs 72 to prevent vibration. As shown in Fig. 2, the armature 13 extends into the lower air gap 104 but not into the upper gap 105 whereby a substantially linear relationship between force and deflection of the armature on coil energization is obtained. The frame 18 is riveted to a base 80 which is sealed to a non-magnetic case 83 having circular indentations 86 and 96 which engage and locate a resilient ring 85 which retains the magnets 61, 62 in position about the coil. Fixed contact assemblies (Fig. 8), each comprise a rigid part 286 with two transverse notches 284, 285 and a spring 282 carrying a contact 283 and riveted at 281 to the part 286. On assembly the part 286 is bent at notch 284 so that its end deflects and stresses the spring 282 and it is then bent at 285 to set the contact gap. A flexible non-magnetic strip 14A is riveted to the members 14, 15. This strip may be rigid if the gap 104 is lengthened by dispensing with the lower horizontal portions of members 14, 15. Specifications 802,758 and 882,684 are referred to.