A semi-active device 20 is provided for damping motion between structures having multi-degrees of freedom. A magnetic field produced by a permanent magnet, a coil, or a combination thereof, change the rheological properties of an MR fluid 40 to effectively lock up the components and the structures to...http://www.google.com.au/patents/US5492312?utm_source=gb-gplus-sharePatent US5492312 - Multi-degree of freedom magnetorheological devices and system for using same
