Patent attributes
An electromagnetic actuator status defines two pairs of poles between which an elongate magnetisable armature can see-saw through a mid position between two home positions defined by two of the poles. A closed low reluctance path in each home position includes a permanent magnet which keeps the armature in either home position. An electromagnet is energised by a current pulse, to repel the armature from one home position and attract it to the other. Resilient energy storage means resists the final movement of the armature towards each pole. A non-magnetisable curved central region of the armature makes rolling contact with a complementary curved surface with the stator to cover and uncover openings therein. The stator is housed within, or forms a fluid chamber and fluid supplied thereto can be delivered selectively through one or the other of the two openings.
