The I-BEAM tactile transducer as described in WORLD INTELLECTUAL PROPERTY ORGANIZATION patent: WO2006063014; granted in 2006, is based in part on US Patent 4,856,071 granted in 1989 to Stanley Marquiss, and contains Patent Art Draft Drawings common to both patents, most especially of the elliptical 'racetrack' coil forming the electromagnetic drive source for the rare earth magnet motional element. 

 

Patent 4,856, 071, is in turn based on US Patent 4,385,210, granted to Stanley Marquiss in 1983, which discloses a dual differential moving magnet transducer, also suitable for use as a tactile low frequency actuator drive motor.

 

The fundamental assumption of the I-BEAM patent is that rare earth moving magnet element driver, does not require any electrical connection to the driving electromagnetic coil, and is linked indeed only by a friction free magnetic flux field, making long motional excursions possible without the possibility of electrical lead failure. Further, the intrinsic magnetic energy product of a given mass of neodymium-iron-boron, N-I-B magnet is substantially greater than an equivalent mass of copper, or other conductor, electromagnetic coil, in a moving coil type of driver, which is much more commonly utilized. 

 

Infra-sound, sub-sonic tactile transducers require near Direct Current motional stability and immense coercive force, in addition to highly efficient heat transfer away from the high current driven electromagnetic elements. Such drivers typically have a very high Q or sharp resonance peak usually placed well below 20 HZ, for maximum efficiency.