Patents Assigned to Diedrich Drilling Equipment, Inc.
  • Flexible plug for obtaining soil samples during drilling operations
    Patent number: 4667754
    Abstract: A flexible plug used in combination with a hollow stem auger and connected drill head which has a hollow housing. The plug includes a plurality of flexible shape-retaining arcuate projections extending towards the plug central axis.
    Type: Grant
    Filed: November 12, 1985
    Date of Patent: May 26, 1987
    Assignee: Diedrich Drilling Equipment, Inc.
    Inventor: John C. Diedrich