Patents by Inventor Frederic J. Singer

Frederic J. Singer 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).

  • Manhole structure and method of making same
    Patent number: 4275757
    Abstract: A multipiece prefabricated manhole assembly and method of making same. The manhole assembly is formed from a cured mixture of a polyester and fiberglass that may have the components thereof wholly or partially assembled in the field to rest on a manhole foundation to provide a manhole structure that is dimensionally stable and one that is substantially impervious to the corrosive action of sewage and gases emanating from the latter such as hydrogen sulphide, methane and the like.
    Type: Grant
    Filed: August 6, 1979
    Date of Patent: June 30, 1981
    Inventor: Frederic J. Singer