Patents by Inventor Frederick D. Wilson

Frederick D. Wilson 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: 4497390
    Abstract: There is provided a self-leveling ladder which is particularly useful on uneven surfaces. The ladder includes an attachment generally U-shaped in form having parallel tubes which are secured to the bottom portion of the legs of the ladder and a tubular bridging mechanism connecting the parallel tubes. Legs are received in the bottom portion of each parallel tube and a plurality of balls are received in the bridge portion and the top portion of the tubes. The balls act to transfer the force from one leg to the other so that when the bottom of the legs are placed on different levels the ladder will automatically level itself.
    Type: Grant
    Filed: May 23, 1983
    Date of Patent: February 5, 1985
    Inventor: Frederick D. Wilson