Patents by Inventor Dennis R. Unruh

Dennis R. Unruh 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: 4253331
    Abstract: This lower link for a three-bar hitch provides a practical way to determine the tension force present in a lower link independent of any bending or other loadings. The link is formed of two bars which are bent out from each other to an intermediate point and then converge together forming a diamond-shaped opening between the bars and the distance between the intermediate points on the bars is measured by a length measuring device; the length being translatable into the tension force on the link.
    Type: Grant
    Filed: September 21, 1979
    Date of Patent: March 3, 1981
    Assignee: The Cessna Aircraft Company
    Inventor: Dennis R. Unruh
  • Patent number: 4175914
    Abstract: This automatic hydraulic cushioning device for cam plate positioning actuators on variable displacement, axial piston pumps eliminates the noise, vibration, and wear caused by hammering of the positioning actuator on the back plate when the actuator is close to full retraction. A supply of fluid under pressure, which is available at the back plate, is channeled to the cam plate positioning actuator. A valve in the actuator blocks off drainage of the fluid whenever the actuator is close to its fully retracted position. This retained fluid becomes a hydraulic stop and cushion for the actuator thus eliminating the hammering as well as the noise, vibration, and wear which results from the hammering.
    Type: Grant
    Filed: May 31, 1977
    Date of Patent: November 27, 1979
    Assignee: The Cessna Aircraft Company
    Inventors: Dennis R. Unruh, Robert J. Martin