Norman G. Gratke

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Elm Grove, WI, US

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Patents Grantslast 30 patents

Information Patent Grant
Membrane switchcores with high resisitivity ink circuits
- Patent number 4,920,342
- Issue date Apr 24, 1990
- W. H. Brady Co.
- Norman G. Gratke
- H03 - BASIC ELECTRONIC CIRCUITRY
Information Patent Grant
Self-referencing capacitive key cell structure and switchcore matri...
- Patent number 4,876,461
- Issue date Oct 24, 1989
- W. H. Brady Co.
- Norman G. Gratke
- H03 - BASIC ELECTRONIC CIRCUITRY
Information Patent Grant
Capacitance membrane switchcore with intertrace capacitive coupling...
- Patent number 4,857,684
- Issue date Aug 15, 1989
- W. H. Brady Co.
- Norman G. Gratke
- H03 - BASIC ELECTRONIC CIRCUITRY