Patents by Inventor Robin Macmillan

Robin Macmillan 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: 6193000
    Abstract: There is provided a rotary drag-type drill bit comprising a bit body having a leading surface comprising a plurality of pads, at least some of the pads each having a wearable abrasive surface including particles of superhard material and defining an outer profile of the pad, at least a part of the outer profile of at least one of the pads being disposed inwardly or outwardly of the outer profile of the other pads. With this arrangement, during initial drilling through softer formation, most of the removal of formation will be effected by the outermost of the abrasive pads and little or no formation will be removed by the more inward pads. Accordingly, the bit will act as a lighter set bit and good rates of penetration may be achieved.
    Type: Grant
    Filed: November 22, 1999
    Date of Patent: February 27, 2001
    Assignee: Camco International Inc.
    Inventors: Douglas Caraway, Robin Macmillan