GB1151901A - Rotary Solenoid. - Google Patents

Abstract

1,151,901. Electromagnets. JASON ELECTRONIC DESIGNS Ltd. 12 May, 1966 [17 Feb., 1965], No. 6898/65. Heading H1P. A rotary solenoid comprises a pair of armatures mounted for rotation within a cylindrical shell, the co-operating faces of the shell and armatures being so shaped that upon rotation the air gaps between them diminishes and thus reduces the reluctance of the magnetic circuit which includes the shell, the air gaps and the armatures. A coil or coils housed within the shell sets up magnetic flux within the circuit which causes the armatures to rotate, the amount of rotation being limited by stops (not shown). In a first embodiment each armature is made up of two semi-circular parts partly displaced relative to one another, the resulting eccentrically curved faces 17 co-operating with similarly curved polepieces 9 of the shell. Spring means may be included to return the armature to the "wide gap" position. In a second embodiment (Figs. 5-7, not shown) each armature comprises a substantially rectangular plate having ends (17a) curved concentrically with the axis of rotation, the air gap between the plate and similarly curved polepieces (9a) being of uniform width but having a length determined by the angular position of the plate. In a third embodiment (not shown) the solenoid includes an armature of each type, it being possible in this case to choose the rate of reduction of the air-gaps in such a way that the torque of the solenoid remains substantially uniform in any angular position.