Patents by Inventor David J. Marquard, II

David J. Marquard, II 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).

  • Five spring regulator
    Patent number: 6484720
    Abstract: An oxygen gas therapy regulator is provided which is small in size and has particularly uniform output characteristics. The regulator uses five springs evenly spaced around a circle concentric with the axis of the regulator piston thereby providing uniform output characteristics.
    Type: Grant
    Filed: October 20, 2000
    Date of Patent: November 26, 2002
    Assignee: Applied Marketing, Inc.
    Inventors: David J. Marquard, II, Ronald J. Johnson