Patents by Inventor Michael D. Kalbfeld

Michael D. Kalbfeld 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).

  • Direct input pilot operated servo valve
    Patent number: 10900502
    Abstract: An electro hydraulic servo valve and a method of controlling pressure therein includes a first stage unit including a moveable direct drive valve, a second stage unit including a centering spring and a second stage spool valve that is fluidly connected to the moveable direct drive valve, and at least one pressure feedback fluid line fluidly connected to the first stage unit. The moveable direct drive valve selectively supplies fluid pressure to the second stage unit. Motion of the second stage unit is arrested using the centering spring and motion of the first stage unit is arrested when pressure is fed back to the first stage unit. A supply pressure or a return pressure is metered using the pressure feedback fluid line.
    Type: Grant
    Filed: July 12, 2018
    Date of Patent: January 26, 2021
    Assignee: Parker-Hannifin Corporation
    Inventors: Alfred W. Otth, Michael D. Kalbfeld
  • DIRECT INPUT PILOT OPERATED SERVO VALVE
    Publication number: 20190063469
    Abstract: An electro hydraulic servo valve and a method of controlling pressure therein includes a first stage unit including a moveable direct drive valve, a second stage unit including a centering spring and a second stage spool valve that is fluidly connected to the moveable direct drive valve, and at least one pressure feedback fluid line fluidly connected to the first stage unit. The moveable direct drive valve selectively supplies fluid pressure to the second stage unit. Motion of the second stage unit is arrested using the centering spring and motion of the first stage unit is arrested when pressure is fed back to the first stage unit. A supply pressure or a return pressure is metered using the pressure feedback fluid line.
    Type: Application
    Filed: July 12, 2018
    Publication date: February 28, 2019
    Inventors: Alfred W. Otth, Michael D. Kalbfeld