Frederick N. Trofimenkoff

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Calgary, CA

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Patents Grantslast 30 patents

Information Patent Grant
Subsurface signal transmitting apparatus
- Patent number 7,093,680
- Issue date Aug 22, 2006
- Weatherford/Lamb, Inc.
- Marvin L. Holbert
- F16 - ENGINEERING ELEMENTS AND UNITS GENERAL MEASURES FOR PRODUCING AND MAINT...
Information Patent Grant
Subsurface signal transmitting apparatus
- Patent number 6,672,383
- Issue date Jan 6, 2004
- Weatherford/Lamb, Inc.
- Marvin L. Holbert
- F16 - ENGINEERING ELEMENTS AND UNITS GENERAL MEASURES FOR PRODUCING AND MAINT...
Information Patent Grant
Subsurface signal transmitting apparatus
- Patent number 6,405,795
- Issue date Jun 18, 2002
- Weatherford/Lamb, Inc.
- Marvin L. Holbert
- E21 - EARTH DRILLING MINING
Information Patent Grant
Subsurface signal transmitting apparatus
- Patent number 6,209,632
- Issue date Apr 3, 2001
- Marvin L. Holbert
- E21 - EARTH DRILLING MINING
Information Patent Grant
Resistance bridge and its use in conversion systems
- Patent number 5,909,132
- Issue date Jun 1, 1999
- Frederick N. Trofimenkoff
- G01 - MEASURING TESTING
Information Patent Grant
Resistance bridge and its use in conversion systems
- Patent number 5,877,637
- Issue date Mar 2, 1999
- Frederick N. Trofimenkoff
- G01 - MEASURING TESTING

Patents Applicationslast 30 patents

Information Patent Application
Subsurface signal transmitting apparatus
- Publication number 20040134652
- Publication date Jul 15, 2004
- Weatherford/Lamb, Inc.
- Marvin L. Holbert
- E21 - EARTH DRILLING MINING
Information Patent Application
Subsurface signal transmitting apparatus
- Publication number 20020189803
- Publication date Dec 19, 2002
- Weatherford/Lamb, Inc.
- Marvin L. Holbert
- F16 - ENGINEERING ELEMENTS AND UNITS GENERAL MEASURES FOR PRODUCING AND MAINT...
Information Patent Application
Subsurface signal transmitting apparatus
- Publication number 20020005282
- Publication date Jan 17, 2002
- Weatherford/Lamb, Inc.
- Marvin L. Holbert
- F16 - ENGINEERING ELEMENTS AND UNITS GENERAL MEASURES FOR PRODUCING AND MAINT...