Michael R. Hoffman

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St. Petersburg, FL, US

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Patents Grantslast 30 patents

Information Patent Grant
Hammer driven soil coring device
- Patent number 4,974,682
- Issue date Dec 4, 1990
- Michael R. Hoffman
- E21 - EARTH DRILLING MINING
Information Patent Grant
Soil coring device with a core ejector mechanism
- Patent number 4,884,638
- Issue date Dec 5, 1989
- Michael R. Hoffman
- E21 - EARTH DRILLING MINING