Electromechanical latching relay and method of operating same

Abstract

A latching relay employing a movable cantilever with a first permanent magnet and a nearby second magnet is disclosed. The permanent magnet affixed to the cantilever is permanently magnetized along its long (horizontal) axis. The cantilever has a first end associated to the first pole (e.g., north pole) of the first magnet, and a second end associated to the second pole (e.g., south pole) of the first magnet. When the first end of the cantilever approaches the second magnet, the first pole of the first magnet induces a local opposite pole (e.g., south pole) in the second magnet and causes the first end of the cantilever to be attracted to the local opposite pole of the second magnet, closing an electrical conduction path (closed state). An open state on the first end of cantilevercan be maintained either by the second pole of first magnet being attracted to a local opposite pole in the second magnet or by a mechanical restoring force of flexure spring which supports the cantilever. A third electromagnet (e.g., a coil or solenoid), when energized, provides a third perpendicular magnetic field about the first magnet and produces a torque on the associated cantilever to force the cantilever to switch between closed and open states. A few alternate embodiments of the relay are also disclosed which include a case where the latching feature is disabled, and another case where an external magnet is used to switch the cantilever.