TREA

David Johnstone

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  • Council Bluffs, IA, US
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Patents Grantslast 30 patents

  • Information Patent Grant

    Track driven sub-base assembly
    • Patent number 9,302,721
    • Issue date Apr 5, 2016
    • David Johnstone
    • E02 - HYDRAULIC ENGINEERING FOUNDATIONS SOIL SHIFTING
  • Information Patent Grant

    Track driven sub-base assembly
    • Patent number 8,905,165
    • Issue date Dec 9, 2014
    • David Johnstone
    • E02 - HYDRAULIC ENGINEERING FOUNDATIONS SOIL SHIFTING
  • Information Patent Grant

    Track driven sub-base assembly
    • Patent number 8,550,193
    • Issue date Oct 8, 2013
    • David Johnstone
    • E02 - HYDRAULIC ENGINEERING FOUNDATIONS SOIL SHIFTING