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Donald L. Duckworth

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  • Roanoke, VA, US
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Patents Grantslast 30 patents

  • Information Patent Grant

    Portable continual mixer
    • Patent number 5,609,416
    • Issue date Mar 11, 1997
    • Donald L. Duckworth
    • B28 - WORKING CEMENT, CLAY, OR STONE
  • Information Patent Grant

    Portable continual mixer
    • Patent number 5,470,147
    • Issue date Nov 28, 1995
    • Donald L. Duckworth
    • B28 - WORKING CEMENT, CLAY, OR STONE