Robert O. Duff

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Farmington, MN, US

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Patents Grantslast 30 patents

Information Patent Grant
Multi-functional doorstop tool
- Patent number 8,960,739
- Issue date Feb 24, 2015
- Robert O. Duff
- E05 - LOCKS KEYS WINDOW OR DOOR FITTINGS SAFES
Information Patent Grant
Doorstop with releasably securable handle
- Patent number 7,976,080
- Issue date Jul 12, 2011
- Robert O. Duff
- E05 - LOCKS KEYS WINDOW OR DOOR FITTINGS SAFES
Information Patent Grant
Portable doorstop with ergonomic advantages
- Patent number 6,557,915
- Issue date May 6, 2003
- Duff's Door Stopper
- Robert O. Duff
- E05 - LOCKS KEYS WINDOW OR DOOR FITTINGS SAFES

Patents Applicationslast 30 patents

Information Patent Application
MULTI-FUNCTIONAL DOORSTOP TOOL
- Publication number 20110254293
- Publication date Oct 20, 2011
- Robert O. Duff
- E05 - LOCKS KEYS WINDOW OR DOOR FITTINGS SAFES