Patents Examined by Robert S. Schultz
  • Drilling apparatus for producing drilled holes having an undercut
    Patent number: 5031709
    Abstract: A drilling apparatus for producing undercut drilled holes and comprising a drill shaft including a bulge portion located between a stop ring mounted on the drill shaft and a drilling head mounted at the free end of the drill shaft, and which narrows towards opposite ends of the drill shaft.
    Type: Grant
    Filed: August 28, 1989
    Date of Patent: July 16, 1991
    Assignee: fischerwerke Artur Fischer GmbH & Co. KG
    Inventor: Artur Fischer