Patents by Inventor Douglas J. Markham

Douglas J. Markham 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).

  • Door mounted exercizing device
    Patent number: 6450929
    Abstract: An exercizing device which includes a pair of handles which are connected to an elastic cord. At the approximate midpoint of the length of the elastic cord, there is mounted a loop strap. The loop strap is to be conducted between a door and a doorjamb with the loop strap being mounted on the doorknob of the door.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: September 17, 2002
    Inventor: Douglas J. Markham