Patents by Inventor Carlos E. M. Maffei

Carlos E. M. Maffei 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).

  • Construction of underground galleries
    Patent number: 4150910
    Abstract: A method of constructing a gallery in which a trench is excavated and the gallery is either constructed in or lowered into the excavation. The gallery is braced internally to withstand external loads applied. Thereafter a controlled backfill is applied around and over the gallery in such manner that with removal of the bracing the backfill acts effectively to form an arch above the gallery which together with the gallery is sufficient to support the overlying covering material up to the ground surface.
    Type: Grant
    Filed: September 23, 1977
    Date of Patent: April 24, 1979
    Assignee: Promon Engenharia SA
    Inventor: Carlos E. M. Maffei