Patents Represented by Attorney George E. Helfrich

Find this attorney in the Justia Lawyer Directory

  • Polyimides containing carbonyl and ether connecting groups
    Patent number: 4820791
    Abstract: New polyimides have been prepared from the reaction of aromatic dianhydrides with novel aromatic diamines containing carbonyl and ether connecting groups between the aromatic rings. Several of these polyimides were shown to be semi-crystalline as evidenced by wide angle x-ray diffraction and differential scanning calorimetry. Most of the semi-crystalline polyimides form tough solvent resistant films with high tensile properties. One of these materials exhibits very high fracture toughness and can be thermally processed.
    Type: Grant
    Filed: February 5, 1987
    Date of Patent: April 11, 1989
    Assignee: United States of America
    Inventors: Paul M. Hergenrother, Stephen J. Havens
  • Control surface actuator
    Patent number: 4773620
    Abstract: A device which actuates aircraft control surfaces is disclosed. The actuator 19 is disposed entirely within the control surface structure 15. Because the actuator 19 is disposed entirely within the control surface 15, the gap 14 between the wing structural box 13 and control surface 15 may be reduced. Reducing the size of the gap 14 is especially desirable for wings with high aspect ratio, wherein the volume of structural box 13 is at a premium.
    Type: Grant
    Filed: March 23, 1987
    Date of Patent: September 27, 1988
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Gerhard E. Seidel