Patent ID: 6265956
Filing Date: 2001-07-24
Classification: H01F

Abstract:
A permanent magnet latching solenoid which comprises a bobbin that defines an axial passage,an electrical winding on said bobbin,magnetically permeable bushings engaged with said bobbin at each end of said passage, said bushings defining with said passage a bore which extends axially of said bobbin from the distal end of one of said bushings to the distal end of the other of said bushings,an armature within said bore, said armature being of an axial length substantially less than the axial length of said bore and being freely reciprocable axially of said bore between two end positions in each of which one end portion of said armature is within the bushing at the respective end of said bore and an opposite end portion of said armature is at least near the bushing at the opposite end of said bore,an operator element attached to said armature,a separate magnetically permeable frame around said bobbin and including opposed end walls extending over said distal ends of said bushings, whereby each of said end walls overlies said distal end of the respective bushing and an assembly comprising said bobbin, said bushings and said armature fits within said frame between said end walls, said distal ends of said bushings being disposed adjacent to and in magnetically permeable coupling relationship with the respective end walls,at least one permanent magnet disposed within said frame between said bushings and located between said frame and said bore, said permanent magnet magnetically coupling with said armature and said frame to magnetically latch said armature in each of said end positions, andsaid coil, when activated by an appropriate electrical pulse, creating a magnetic field coupling through said frame, armature and bushings to drive said armature from either of said end positions toward the other of said end positions.