Patents by Inventor David William Classen

David William Classen 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).

  • Concrete step
    Patent number: 8935894
    Abstract: A concrete step has a trough with a base and two side walls. The side walls project upwardly from the base and are positioned at opposite ends of the base. At least one of the sidewalls has an inwardly projecting flange spaced away from the base by approximately the height of the step. Concrete fills the trough at least up to the inwardly projecting flange, and together a top surface of the concrete and at least a portion of the inwardly projecting flange form a top surface/tread of the step.
    Type: Grant
    Filed: September 13, 2013
    Date of Patent: January 20, 2015
    Inventor: David William Classen
  • Concrete step
    Patent number: D733932
    Type: Grant
    Filed: September 13, 2013
    Date of Patent: July 7, 2015
    Inventor: David William Classen