Patents Assigned to Elizabeth Jean Hillier
  • Drilling bit
    Patent number: 4218162
    Abstract: A drilling bit has cutting edges radiating from its axis, each being a segmental part of a circular cutter the axis of which is substantially tangential to a circle centered on the bit axis, the cutters being at different distances from the bit axis. The cutters may be rotated to enable worn cutting edges to be replaced and the extremities of all cutting edges are substantially in a plane normal to the bit axis.
    Type: Grant
    Filed: November 1, 1978
    Date of Patent: August 19, 1980
    Assignee: Elizabeth Jean Hillier
    Inventor: Raymond G. Hillier