Patent ID: 6836201
Filing Date: 2004-12-28
Classification: H01F

Abstract:
An actuator, comprising:an annular electromagnet having a bore therethrough with a bore axis; a ferromagnetic plunger disposed within the bore and slidable therein parallel to the bore axis, the plunger having a first end face and a second end face; a first permanent magnet positioned outside of the bore and in facing relation to the first end face of the plunger along the bore axis, the first permanent magnet attracting the plunger thereto; a second permanent magnet positioned outside of the bore and in facing relation to the second end face of the plunger along the bore axis, the second permanent magnet attracting the plunger thereto, the plunger being slidable in the bore between a first position with the first end face adjacent to the first permanent magnet and a second position with the second end face adjacent to the second permanent magnet; and a bipolar electrical DC power supply operatively connected to the electromagnet through a sense switch, whereby a polarity of the electromagnet may be reversed by operation of the sense switch, the plunger being retained adjacent to one of the permanent magnets when the electromagnet is not energized.