John Duff

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North Bay, CA

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Patents Grantslast 30 patents

Information Patent Grant
Hydraulic impactor
- Patent number 4,363,258
- Issue date Dec 14, 1982
- Joy Manufacturing Company
- John Duff
- F01 - MACHINES OR ENGINES IN GENERAL ENGINE PLANTS IN GENERAL STEAM ENGINES
Information Patent Grant
Hammer
- Patent number 4,344,353
- Issue date Aug 17, 1982
- Joy Manufacturing Company
- John Duff
- F01 - MACHINES OR ENGINES IN GENERAL ENGINE PLANTS IN GENERAL STEAM ENGINES