Patents by Inventor David N. Hoffman

David N. Hoffman 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).

  • Patent number: 6012285
    Abstract: A vertically-extending L-shaped exhaust pipe and method of manufacturing same are disclosed. The exhaust pipe includes a drain hole located at the bottom of the horizontal portion of the exhaust pipe for allowing liquids to drain from the pipe in order to avoid harming upstream exhaust system or engine components. An elliptically shaped guide is welded into an arcuate slot immediately upstream of the drain hole and is angled in the downstream direction so as to direct the flow of liquid toward the drain opening and away from upstream exhaust system components. The present invention is simple to manufacture, eliminates the need for a noisy flapper lid, and maintains the structural integrity of the exhaust pipe.
    Type: Grant
    Filed: March 19, 1998
    Date of Patent: January 11, 2000
    Assignee: Wacker Corporation
    Inventors: Todd J. Lutz, David N. Hoffman