Patents by Inventor William F. Armstrong

William F. Armstrong has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4879056
    Abstract: An improved method of inducing a change in the dynamic torque transmission of an electrorheological fluid in response to an electric field at low current comprising the steps of: (a) selecting a nonconductive liquid phase (e.g. high dielectric hydrocarbon oil); (b) dispersing in the nonconductive liquid phase a particulate phase substantially free of adsorbed water (e.g. zeolite); and (c) subjecting the resulting electrorheological fluid to an electric potential in excess of about one kilovolt at a current density of less than about one-third microamp per square inch. Such a method achieves a rate of increase of dynamic transmission of torque per unit voltage, dM/dV, in excess of about 0.034 ft-lbs.times.10.sup.-3 /kV and a ratio of dynamic transmission of torque at an electric field strength of at least 2.4 kV to the dynamic transmission of torque at zero field strength, M/Mo, of at least about 2.
    Type: Grant
    Filed: October 21, 1987
    Date of Patent: November 7, 1989
    Assignee: Board of Regents Acting for and on Behalf of University of Michigan
    Inventors: Frank E. Filisko, William F. Armstrong