Patents Assigned to John V. Pehrson
  • Patent number: 4240208
    Abstract: A telescoping surveying rod carries on its upper end a laser beam sensor which reacts to a rotating laser beam of conventional type located at a distance. The sensor preferably has a vertical, triangular cross-section piece which supports on each face three solar cells, each cell emitting a signal when the beam strikes it, depending upon whether the sensor is at above or below level. The sensor is actuated throughout 360.degree. and hence need not be pointed at the beam source. An eye level readout device on the lowermost rod section has three lights which are illuminated depending upon which cell is energized. The rod is raised or lowered until the center light is illuminated, whereupon the rod marking indicates the distance below beam level of the foot of the rod.
    Type: Grant
    Filed: October 1, 1979
    Date of Patent: December 23, 1980
    Assignee: John V. Pehrson
    Inventor: Marie S. Pehrson