Fred W. Hefer

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Houston, TX, US

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Patents Grantslast 30 patents

Information Patent Grant
Printed-circuit disc for stringing geophones
- Patent number 4,594,698
- Issue date Jun 10, 1986
- Oyo Corporation
- Fred W. Hefer
- G01 - MEASURING TESTING
Information Patent Grant
Horizontal geophone transducer assembly
- Patent number 4,525,819
- Issue date Jun 25, 1985
- Oyo Corporation, U.S.A.
- Fred W. Hefer
- G01 - MEASURING TESTING