Patents by Inventor Theodore E. Schwellnus

Theodore E. Schwellnus 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).

  • Drawing instruments
    Patent number: 4819338
    Abstract: A drawing board and drawing instrument combination is provided. The drawing board has grooves along three of its edges and at 45.degree. across the corners which can receive tongues provided on either side of a flat drawing instrument. The instrument has a number of straight edges which overlie the board in use and which make different angles to the edge of the board. The instrument serves as a T-square and also as a set-square, and is reversible.
    Type: Grant
    Filed: March 16, 1987
    Date of Patent: April 11, 1989
    Assignee: Cibela Patents C.C.
    Inventors: Christiaan B. Lategan, Theodore E. Schwellnus