Patents Examined by Richard E. Fabreau
  • Fluid operated undercutter
    Patent number: 4186810
    Abstract: An undercutter comprising a slotted tubular body in which is mounted an extendable and retractable cutting head for undercutting a bore into which the tubular body is positioned and rotated. The cutting head includes a fluid-operated reciprocally movable piston, the reciprocating rate of which is determined by an annular liner positioned between the outer wall of the piston body and the inner wall of the piston cavity.
    Type: Grant
    Filed: July 5, 1977
    Date of Patent: February 5, 1980
    Assignees: John MacDonald & Company (Pneumatic Tools) Limited, David Thomson Allan
    Inventor: David T. Allan