View Full Version : Patent 4123675: This For Real?

23rd February 2009, 08:48 PM

A viscous-fluid inertia damper, which damper comprises a housing composed of a nonferromagnetic material and having a chamber therein, a seismic mass containing a permanent magnet disposed in the housing chamber and in a closely spaced-apart relationship with the internal wall surface of the chamber, means to couple the housing to a dynamic element whose energy is to be dampened, and a ferrofluid of selected viscosity in the remaining volume of the chamber, the ferrofluid distributed generally uniformly in the volume, the magnetic saturation of the ferrofluid by the magnetic field of the permanent magnetic levitating the seismic mass in the damper, and the viscosity of the ferrofluid in the magnetic field providing a means to dissipate energy from the dynamic system through viscous shear forces in the ferrofluid disposed between the wall surface of the chamber and the seismic mass.

This for real? Yes, I know some patents are totally wacky, but it's always good to ask anyway.


23rd February 2009, 09:09 PM
Makes sense to me. I recall ferrofluids being used in similar things.

23rd February 2009, 09:16 PM
I have this in my car (note I don't read patents so I just read the description of this above). Basically it's a shock absorber where they change the viscosity of the fluid based on what the computers things it should be doing for things like road conditions, cornering etc.


Magnetic Selective Ride Control. The optional F55 Magnetic Selective Ride Control suspension features magneto-rheological dampers able to detect road surfaces and adjust the damping rates to those surfaces almost instantly for optimal ride and body control. Magnetic Ride Control debuted on the 2003 50th Anniversary Edition Corvette, and is the world’s fastest reacting suspension, replacing mechanical valves with nearly instantaneous reactions of magneto-rheological fluid. The system has been improved for the C6, allowing drivers more differentiation in character between the system’s two settings, “Tour” and “Sport.”

Dan O.
23rd February 2009, 09:44 PM
Ferrofluids have been used for mechanical damping in speakers for over 25 years link (http://www.ferrotec-europe.de/fr/htmls/fluid.audio.overview.php). So it makes sense that the patent office would issue a new patent for the use of ferrofluids in a mechanical damping application now.

However, having a magnetic element on the moving portion of a seismic instrument does not make sense. It's going to generate a false reading every time there is a magnetic anomaly in the area such as when a UFO flies overhead.