Patents Examined by William Fridig, Jr.
  • Patent number: 4979575
    Abstract: A method and an arrangement for drilling a hole in a rock (6), wherein a preliminary hole is drilled first, whereafter the drilling is interrupted. Joints between a drill boom (2) and a feeding beam (5) and/or the feeding beam (5) in its longitudinal direction are released so as to move freely in order that the boom (2) and the feeding beam (5) would take a substantially strainless position and the angles (.alpha., .beta.) of the joints and the position of the feeding beam (5) and the drill rod are measured. Thereafter the direction and distance from the preliminary hole (C) to the terminal point (B) of the originally designed hole is computed, and the drilling of the hole is completed.
    Type: Grant
    Filed: June 1, 1989
    Date of Patent: December 25, 1990
    Assignee: Oy Tampella Ab
    Inventors: Rolf Strom, Veijo Nurmi, Risto Wisakanto