Patents by Inventor Stewart M. Duncan

Stewart M. Duncan 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: 4942924
    Abstract: A liner setting assembly is useful in setting a liner into a casing string secured in a borehole of a well. The liner setting assembly includes a cone and a cage. The cone enables slidably fitting over the liner, the cone having grips with an oblique notched face forming an engaging surface. The cage receives the cone and includes a second set of grips having oblique notched faces. The cone and cage assembly is secured to the casing string by the grips. Since the cone has a sliding fit in relation to the liner, the operator can reciprocate and rotate the liner even after the cage and cone assembly has been securely engaged with the casing string in the borehole, thereby enabling a positive indication of the correct set position prior to the cement bonding of the liner to the wall of the well.
    Type: Grant
    Filed: February 13, 1989
    Date of Patent: July 24, 1990
    Inventor: Stewart M. Duncan