Patents by Inventor Robert Scot Lehmann

Robert Scot Lehmann 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).

  • Hydraulic system having a pressure compensator
    Patent number: 7204185
    Abstract: A hydraulic system having a source of pressurized fluid and a fluid actuator with a first chamber and a second chamber. The hydraulic system also has a first valve configured to selectively fluidly communicate the source with the first chamber and a second valve configured to selectively fluidly communicate the source with the second chamber. The hydraulic system also has a supply passageway and a signal passageway each disposed between the first and second valves in parallel. The hydraulic system also has a proportional pressure compensating valve configured to control a pressure of a fluid directed between the source and the first and second valves. The hydraulic system further has a fluid passageway disposed between the supply and signal passageways to fluidly communicate the supply and signal passageways.
    Type: Grant
    Filed: April 29, 2005
    Date of Patent: April 17, 2007
    Assignees: Caterpillar Inc, Shin Caterpillar Mitsubishi Ltd
    Inventors: Pengfei Ma, Gene Richard St. Germain, Jiao Zhang, Aleksandar M. Egelja, Robert Scot Lehmann, Michael A. Sorokine