Ruth B. Leff

Follow

Person

Milwaukee, WI, US

People

Patents Grantslast 30 patents

Information Patent Grant
Communication aid using multiple membrane switches
- Patent number 5,910,009
- Issue date Jun 8, 1999
- Ruth B. Leff
- G09 - EDUCATION CRYPTOGRAPHY DISPLAY ADVERTISING SEALS
Information Patent Grant
Cabinet for instructional electronic communication
- Patent number D363741
- Issue date Oct 31, 1995
- Ruth B. Leff
- D19 - Office supplies
Information Patent Grant
Dual mode switch for handicapped
- Patent number 5,382,791
- Issue date Jan 17, 1995
- Ruth B. Leff
- G08 - SIGNALLING
Information Patent Grant
Communication aid
- Patent number 4,954,083
- Issue date Sep 4, 1990
- Ruth B. Leff
- G09 - EDUCATION CRYPTOGRAPHY DISPLAY ADVERTISING SEALS
Information Patent Grant
Communication aid with sequential lighting
- Patent number 4,915,632
- Issue date Apr 10, 1990
- Ruth B. Leff
- G09 - EDUCATION CRYPTOGRAPHY DISPLAY ADVERTISING SEALS
Information Patent Grant
Communication aid
- Patent number 4,761,633
- Issue date Aug 2, 1988
- Ruth B. Leff
- G09 - EDUCATION CRYPTOGRAPHY DISPLAY ADVERTISING SEALS