Patents by Inventor Graeme D. Dufferwiel

Graeme D. Dufferwiel 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: 5195403
    Abstract: A method of producing a composite cutting insert for a twist drill includes the steps of cutting an intermediate blank from a composite diamond compact. The intermediate blank comprises a relatively broad tungsten carbide strip with a relatively narrow polycrystalline diamond strip at one edge. First and second cutting insert halves are cut from the intermediate blank, each cutting insert half defining a cutting edge of the diamond material. The cutting insert halves are arranged back-to-back to form a composite cutting insert, with the cutting edges on opposite sides of a central plane. The cutting edges are arranged to define a chevron shaped composite cutting edge. The cutting insert halves are preferably brazed together to form a unitary cutting insert. The invention extends to a method of producing a twist drill including the steps of forming a slot-shaped seat diametrally in the end of a twist drill body, and brazing the composite cutting insert into the seat.
    Type: Grant
    Filed: February 28, 1992
    Date of Patent: March 23, 1993
    Assignee: De Beers Industrial Diamon Division Limited
    Inventors: Mohammad N. Sani, Graeme D. Dufferwiel