GB846004A - Improvements in or relating to relay-operating electromagnets with armatures capableof limited rotary motion - Google Patents

Abstract

846,004. Electromagnets. LANDIS & GYR A.G. Nov. 8, 1956 [Nov. 9, 1955], No. 34197/56. Class 35. In a relay-operating electromagnet which includes a stator having a substantially closed iron shield 2 magnetically screening the electromagnet and an armature 12, 13 capable of limited rotary motion, there being passive and at least one active air gap between the armature and stator, the passive air gap is of uniform width and is formed between a conical portion 12 of the armature and a conical bore 11 in the core 8 of a coil 10 surrounding the conical portion 12. The active air gaps are formed between bent-over poles 5, 6 and 14, 15 of a stator pole plate 3 and an armature plate 13 respectively screwed to the end 1 of the shield 2 and riveted to the armature cone 12. The armature rotates on a pivot 20 and a spindle 22 which transmits the output movement, respectively borne by a thrust bearing 21 and an end bearing 23. The armature rest position is determined by a biasing spiral spring 18 and a stop 25 extending from one of the coil bobbin flanges, and when the coil 10 is energized armature rotation is limited by a similar stop 26. The armature is biased towards the left-hand end of Fig. 1, when inoperative by the spring 18 and when operative by the magnetic attraction being greater in the active than in the passive air gap. Armature concentricity is achieved by pulling it to the right to engage its conical part 16 with an end of the core 8, and then tightening pole plate securing screws 4 passing through enlarged holes in the shield end 1.