Patents by Inventor Gustav Keller

Gustav Keller 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-pit lining and method of making and installing same
    Patent number: 4102088
    Abstract: A manhole-pit lining is formed of a base, a tubular middle portion, and a top to which a manhole cover is fittable. The base is custom-made in accordance with the particular requirements of the pit being lined. The middle tube provided with pipe connections is then fitted over this base with the pipe connections aligned with the trough formed in the base and is secured thereto by means of an epoxy resin. The middle and base are then placed in an excavation and the pipe connections on the middle are hooked up to the pipes to be joined at the manhole pit. The cover is secured to the top and the excavation is then backfilled. The entire assembly is made of waterproof reinforced concrete and the middle tube itself may be constituted as a standard waterproof pipe section.
    Type: Grant
    Filed: February 14, 1977
    Date of Patent: July 25, 1978
    Inventors: Gustav Keller, Gerhard Enssle