Patents by Inventor Carlheinz Mannhardt

Carlheinz Mannhardt 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).

  • Ladder
    Patent number: 4967879
    Abstract: A ladder, especially for use in manholes, where the rungs are mounted in double-walled sidepieces via respective sleeves. Each sleeve has a body wall that, to uniformly support introduced forces, extends through both walls of a sidepiece and, especially from the outside, is arrested by connections between the rung and sleeve on the one hand and the sleeve and sidepiece on the other hand. At the same time, an outwardly directed base of the sleeve protects not only the rung but also the outer wall of the sidepiece.
    Type: Grant
    Filed: February 23, 1989
    Date of Patent: November 6, 1990
    Assignee: Zarges Leichtbau GmbH
    Inventors: Ulrich Klafs, Carlheinz Mannhardt, Heinz Pecher, Oswald Riedl