Patents by Inventor Martin C. Dennis

Martin C. Dennis 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).

  • Ladder levelling device
    Patent number: 6336521
    Abstract: Prior ladder levelling devices are difficult to adjust to a surface because it is necessary to unweight the ladder at the same time as adjusting. The present invention provides opposed locking brackets so that adjustment can be made by releasing a locking plate on just one bracket.
    Type: Grant
    Filed: September 13, 2000
    Date of Patent: January 8, 2002
    Inventor: Martin C. Dennis