Patent ID: 6104270
Filing Date: 2000-08-15
Classification: B66C,H01F

Abstract:
A lifter comprising:a reversible magnet having a magnetization curve, a commuting coil with a longitudinal axis, and opposite polarities oriented along said longitudinal axis;at least a working point on said magnetization curve of said reversible magnet;a ferromagnetic core having sides and a base, and adapted to contact a load to be lifted by said lifter;a pair of permanent magnets each arranged on one of said sides of said ferromagnetic core with their polarities oriented along an axis perpendicular to said longitudinal axis of said commuting coil;a first magnetic sensor disposed adjacent said base of said ferromagnetic core;a second magnetic sensor disposed above said permanent magnets for measuring the magnetic flux passing through said reversible magnet; anda safety device for processing signals transmitted by said first and second magnetic sensors and obtaining said working point of said lifter on the magnetization curve of said reversible magnet.