Patents by Inventor David Maxwell Cranswick

David Maxwell Cranswick 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: 5893431
    Abstract: A basement emergency exit assembly has a ladder for exiting from a basement window. The window is held within tracks mounted at the interior of the window frame. By moving the bottom of the ladder away from the wall, the window is permitted to slide down the track out of its frame and the ladder is positioned at an angle for easy egress. The window can either fall directly into a pocket within a wall, or, the tracks can be swung out as the ladder is moved thereby pulling the window out of frame and causing it to slide along the tracks until it is clear of the window opening.
    Type: Grant
    Filed: January 21, 1998
    Date of Patent: April 13, 1999
    Inventors: David Maxwell Cranswick, Keith S.J. Neumark