Vibration transducer with dual opposed magnetic assemblies and counterbalanced mass

Claim 1

A magnetic transducer comprising: a first magnet assembly including a first magnetizable housing having a bottom and upstanding sidewalls defining a first upwardly opening interior volume with a central body axis normal to said bottom, a pair of magnetic field generating means secured within said first volume with the opposite poles of each field generating means aligned along said axis, a like polarity pole of each said pair being arranged in confronting relation, and coil means secured in said interior volume in flux cutting relationship with the magnetic fields generated by said pair; and a second magnetic assembly arranged above said first magnetic assembly, said second magnetic assembly including a second magnetizable housing having a top and downwardly depending sidewalls partially surrounding the sidewalls of said first housing, an additional magnetic field generating means secured to the inner surface of said top, the facing poles of said additional magnetic field generating means and the proximate one of said pair of magnetic field generating means having the same polarity so that said first and second magnetic assemblies are mutually magnetically repelled with mutual motion therebetween being confined by said sidewalls to motion substantially along said axis, and a mass secured to said second housing for providing a force of sufficient magnitude to counteract the magnetic force of repulsion between said first and second magnetic assemblies.