GB871115A - Improvements in or relating to electromagnetic motor devices - Google Patents

Abstract

871,115. Oscillating motors. BIRD, W. G. May 19, 1959 [March 20, 1958; May 22, 1958], Nos. 9014/58 and 16467/58. Class 35. [Also in Group XXXVII] An oscillatory electric motor for imparting step-by-step angular movements to a shaft such as that of a rotary selector switch comprises a coil 1 which when energized initially moves an armature 4 in an axial direction; this movement, by means of the teeth of a dog clutch 7, 8, Fig. 4, causes an initial angular movement of the armature 4 such as to register, Fig. 6, each pole piece 10 of the armature with only one pole piece 11 of the stator 3 whereupon the magnetic force between the pole pieces 10, 11 produces a further angular movement, Fig. 8, of the armature. The armature is biased axially away from the stator 3 by a helical phosphorbronze spring 5 and is supported, together with the clutch member 7, by a spindle 6 borne by an oil-impregnated sintered bronze bearing 16. Armature slots 21 engaged by pins 20 fixed to the stator yoke 13 ensure armature movement in the correct angular direction, and either a friction pad 18 or a rectifier, Fig. 10 (not shown), shunted across the coil 1 may be provided to prevent oscillation of the armature when it returns to the rest position. To provide a selective drive in either of the two angular directions another embodiment has two stators between which is a single armature, and a double dog clutch, and energizing circuits embodying change-over switches are disclosed. In another embodiment the armature has a single stator but auxiliary coils on the latter are selectively energized to provide the initial angular movement in one or the other direction.