Patents by Inventor David F. Plant

David F. Plant 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: 6257610
    Abstract: A foot-operated propulsion apparatus for a wheelchair and/or other selected devices such as desk chairs and furniture. In one embodiment, the apparatus includes a support structure coupled to the selected device and having at least one roller aperture. A roller element having a circular cross-sectional shape is received in the roller aperture and is rotatable relative to the support structure about a rotation axis or a plurality of rotation axes. The roller element has a first external portion projecting upwardly from the aperture to engage the user's foot and a second external surface portion projecting downwardly through the aperture to engage the ground or other support surface. As the user engages the roller element and rotates the element by foot, the propulsion apparatus and the device to which it is coupled move along the ground. The user can directly engage the roller element or can engage a brake device coupled to the roller element to slow the propulsion device.
    Type: Grant
    Filed: February 16, 2000
    Date of Patent: July 10, 2001
    Inventor: David F. Plant
  • Patent number: 4452225
    Abstract: An improved, portable, auxiliary radiant chimney effect heater or reradiator including an inverted, conical chimney placed over and heated to the infrared spectrum by an open flame such as that provided by the burner of an otherwise conventional cooking stove. A semi-parabolic reflector surrounds the chimney and the chimney is located at the approximate focal point of the reflector. The invention functions as a chimney, by drawing combustion by-products into the chimney whereupon the chimney is heated and consumes the by-products, particularly noxious fumes and water vapor. The reflector may be provided with a casing and a handle to ease portability of the heater. For the sake of safety, forward, semi-circular guard bars and a rear, guard plate may be provided.
    Type: Grant
    Filed: June 14, 1983
    Date of Patent: June 5, 1984
    Inventor: David F. Plant