Douglas A. Engel

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Englewood, CO, US

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Patents Grantslast 30 patents

Information Patent Grant
Puzzle amusement device
- Patent number 5,106,093
- Issue date Apr 21, 1992
- Douglas A. Engel
- A63 - SPORTS GAMES AMUSEMENTS
Information Patent Grant
Puzzle amusement device
- Patent number 4,735,418
- Issue date Apr 5, 1988
- Douglas A. Engel
- A63 - SPORTS GAMES AMUSEMENTS
Information Patent Grant
Puzzle amusement device
- Patent number 4,487,417
- Issue date Dec 11, 1984
- Douglas A. Engel
- A63 - SPORTS GAMES AMUSEMENTS
Information Patent Grant
Puzzle
- Patent number 4,415,158
- Issue date Nov 15, 1983
- General Symmetrics, Inc.
- Douglas A. Engel
- A63 - SPORTS GAMES AMUSEMENTS