John F. Johannsen

DM David Manufacturing: 1 patents #1 of 2Top 50%

📍 Charles City, IA: #1 of 2 inventorsTop 50%

🗺 Iowa: #47 of 364 inventorsTop 15%

Overall (1982): #20,761 of 81,411Top 30%

Patents 1982

Issued Patents 1982

Showing 1–1 of 1 patents

Patent #	Title	Co-Inventors	Date
4312750	Grain cleaning apparatus	Keith Braun	1982-01-26