Electromagnetic driven device

摘要

An electromagnetically driven device has a coil and a plunger movably inserted in the coil between an inserted and ejected positions. An armature carrying a permanent magnet is provided at one end of the coil for holding the plunger in the inserted position by a magnetic attractive force developed between the armature and the plunger when the coil is deenergized. A yoke is provided between the permanent magnet and the armature for establishing a magnetic circuit therebetween with a predetermined reluctance developed between the armature and the yoke.