Patents by Inventor Charles E. Foster

Charles E. Foster 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: 4219755
    Abstract: An electromotive actuator comprises a hollow cylinder within which is an electroexpansive body having attached to each end a metal cup with slotted sides. Inside of each cup there is positioned an electroexpansive disc which, in the absence of excitation, causes the slotted sides, which are called fingers hereinafter, to bend outward, and in the presence of excitation enables them to return to their original position. In the absence of excitation the fingers clamp tightly against the inner surface of the cylinder and in the presence of excitation they spring inwardly and release that surface. By sequencing the excitation of the respective discs and the central body in one embodiment of the invention, the assembly can be made to move in either direction and thereby move an externally extending rod. In another embodiment of the invention, by properly sequencing the excitation of the discs and central body, high torque and fine angular resolution may be obtained.
    Type: Grant
    Filed: March 18, 1977
    Date of Patent: August 26, 1980
    Assignee: Physics International Company
    Inventors: Cormac G. O'Neill, Charles E. Foster