Patents Assigned to Terre AG fur Tiefbautechnik
  • Percussion drilling apparatus
    Patent number: 4821813
    Abstract: A percussion drilling apparatus has a control unit in which a displacement reversing unit is arranged axially adjacent to a piston control unit, with the result that the control edges for the apparatus advance and apparatus return can be arranged in separate control sleeves. This control unit makes it possible to achieve better apparatus characteristics and higher overall efficiency of the apparatus.
    Type: Grant
    Filed: March 24, 1987
    Date of Patent: April 18, 1989
    Assignee: Terre AG fur Tiefbautechnik
    Inventors: Gustav Jenne, Dietmar Jenne