Barry A. Spencer

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Redmond, WA, US

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Patents Grantslast 30 patents

Information Patent Grant
Rotary cutterhead for an earth boring machine
- Patent number 4,234,235
- Issue date Nov 18, 1980
- The Robbins Company
- Richard J. Robbins
- E21 - EARTH DRILLING MINING
Information Patent Grant
Rotary cutterhead for an earth boring machine
- Patent number 4,193,637
- Issue date Mar 18, 1980
- The Robbins Company
- Barry A. Spencer
- E21 - EARTH DRILLING MINING