with locking devices located near head or foot

Industry

  • CPC
  • E21D15/12
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Patents Grantslast 30 patents

  • Information Patent Grant

    Variable yielding mining crib support column

    • Patent number 5,439,325
    • Issue date Aug 8, 1995
    • Mountainland Support, Inc.
    • Chris D. Kitchen
    • E21 - EARTH DRILLING MINING
  • Information Patent Grant

    Collapsible crib mining support column

    • Patent number 5,342,150
    • Issue date Aug 30, 1994
    • Mountainland Support, Inc.
    • Chris D. Kitchen
    • E21 - EARTH DRILLING MINING
  • Information Patent Grant

    2893679

    • Patent number 2,893,679
    • Issue date Jul 7, 1959
    • E21 - EARTH DRILLING MINING
  • Information Patent Grant

    2208885

    • Patent number 2,208,885
    • Issue date Jul 23, 1940
    • E21 - EARTH DRILLING MINING
  • Information Patent Grant

    1979503

    • Patent number 1,979,503
    • Issue date Nov 6, 1934
    • E21 - EARTH DRILLING MINING
  • Information Patent Grant

    1921542

    • Patent number 1,921,542
    • Issue date Aug 8, 1933
    • E21 - EARTH DRILLING MINING
  • Information Patent Grant

    1818633

    • Patent number 1,818,633
    • Issue date Aug 11, 1931
    • E21 - EARTH DRILLING MINING
  • Information Patent Grant

    1714024

    • Patent number 1,714,024
    • Issue date May 21, 1929
    • E21 - EARTH DRILLING MINING