Patents by Inventor Mark S. Francis

Mark S. Francis 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: 4497608
    Abstract: A digger for digging out substantially vertically-sided holes e.g. for gravestone monument foundations, is in the form of an attachment adapted to be connected on the dipper stick of a backhoe machine. The attachment has a downwardly-depending digger frame pivoted at its upper end to an attachment frame which is connected to the free end of the dipper stick. A vertically extending operating shaft extends upwardly relative to the digger frame and is connected through a pair of lower linkages to the sections of a clam shell bucket mounted on the lower end of the digger frame. The upper end of the operating shaft connects through a connecting link and a rocking lever to the piston of the dipper stick piston and cylinder arrangement.
    Type: Grant
    Filed: June 13, 1983
    Date of Patent: February 5, 1985
    Assignee: The Trustees of The Toronto General Burying Grounds
    Inventors: Roy J. P. Sheppard, Howard S. Thornhill, Mark S. Francis