Patents by Inventor Donald U. Shaffer

Donald U. Shaffer 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: 4688828
    Abstract: A tubing joint for the corrosion protection of a production string of metal tubes having one or more annular grooves on the surface of the tube for the inclusion of sacrificial metal rings. Preferably, the metal rings are substantially coincident with the tubing surface.
    Type: Grant
    Filed: April 2, 1986
    Date of Patent: August 25, 1987
    Inventor: Donald U. Shaffer
  • Patent number: 4550895
    Abstract: A ram seal element adapted for use with a ram block and ram block holder in a blow out preventer apparatus to provide sealing of drill strings of varying diameters. The ram seal element is a semi-circular elastomer having a diametrical portion and a circumferential portion. The diametrical portion includes a center collar section and two side sections with the collar section being adapted for sealing contact with the drill string. The diametrical portion is provided on its outer side surface with a longitudinal channel defining an expansion zone into which the seal can expand uniformly to accommodate drill strings of increasing size.
    Type: Grant
    Filed: September 24, 1984
    Date of Patent: November 5, 1985
    Inventor: Donald U. Shaffer
  • Patent number: 4448255
    Abstract: A rotary blowout preventer having a radially compressible packing to be sealingly engaged with and rotated by a drill pipe or kelly and a hydraulically actuated wedging piston for compressing the packing is provided with a rotatable bearing support which in an exemplary embodiment includes an inverted truncated cone interposed between the packing and the piston, which is rotatably mounted to the piston by a plurality of bearing races, along with a thrust bearing interposed between the packing and the housing enable the packing to rotate relative to the housing and prevents upward axial motion of the packing.
    Type: Grant
    Filed: August 17, 1982
    Date of Patent: May 15, 1984
    Inventors: Donald U. Shaffer, Gary M. Oulrey