Patent ID: 8179217

Claim:
A polar electromagnet device comprising: a drive shaft comprising an axis center supported so as to reciprocate in an axis center direction at a center hole of a spool wound with a coil; a fixed iron core disposed within the center hole of the spool; a movable iron core attached to a lower end of the drive shaft on the axis center, wherein the movable iron core comprises: a first movable iron piece; a second movable iron piece, wherein the first moveable iron piece is disposed radially adjacent to the second movable iron piece with respect to the axis center; a permanent magnet directly sandwiched by the first movable iron piece and the second movable iron piece, wherein the permanent magnet is disposed radially adjacent to the second moveable iron piece with respect to the axis center; and a coil spring disposed on the drive shaft and configured to bias the movable iron core away from the fixed iron core, wherein the drive shaft is reciprocated with the movable iron core which reciprocates based on excitation and demagnetization of the coil.