JO1771B1 - Bistable magnetic actuator - Google Patents

Abstract

A bistable magnetic actuator having a housing (1) of magnetic material within which an armature (7) of magnetic material is axially movable between two stable positions, the ends of the housing being closed by pole pieces (4,5), the armature having a push rod (9) axially slidably guided through one or each of the pole pieces, the housing containing a magnet coil (3) which extends inside the housing substantially from one pole piece to the other, the axial dimension of the armature being such that when the actuator is in either of its stable positions, an end of the armature is in abutment with or in close proximity to a corresponding one of the pole pieces and there is an axial gap (14) between the other end of the armature and the other of the pole pieces, permanent magnets (12,13); being provided which act on the armature and pole pieces in such a way as to cause the armature to be magnetically retained in whichever of the two stable positions it is situated, without energization of the coil, energization of the coil by an appropriately directed electric current pulse causing an increase in flux density at the end of the armature adjacent the gap and a decrease in flux density at the other end of the armature, resulting in movement of the armature into the other stable position, where it will stably remain after the coil is de-energized.