| 1930 DUFF CHARLES Exercising Machine Patent |
| 1836 DUFF Steam Puppet Valve MURPHY Patent 52637 |
| 1871 DUFF Pin Wheel Childrens Toy GREER Patent 47807 |
| 1952 DUFF JOHN Golf Ball Cleaner Patent Print |
| 1956 DUFF NORTON CO Push Pull Jack Patent Print |
| 2000 DUFF Design Combined Golf Ball Tee Patent 46076 |
| 1931 DUFF EWEN Apparel Garment Patent Print Art |
| 1969 SAMUEL DUFF Battery Cages Patent Print Art |
| 1957 DUNCAN S DUFF JULIA DUFF (+3) Ball Patent |
| 1933 DUFF CHARLES Exercising Machine Patent |
| 1932 DUFF EWEN Apparel Garment Patent Print Art |
| 1920 DUFF Doll MOOV DOLL MANUFACTURING Patent 19900 |
| 1922 JOHN DUFF Figure Toy Patent Print Art |
| 1969 DUFF SAMUEL Battery Cages Patent Print Art |
| 1932 DUFF EWEN Garment KOPS BROTHERS INC Patent |
| 1932 DUFF CHARLES Exercising Machine Patent |
| 1922 DUFF MFG COMPANY Lifting Jack Patent Print |
| 1924 DUFF Bumper For Automobiles Patent Print |
| 1930 DUFF Combination Shoe And Skate Patent |
| 1931 COOPER DUFF Apparel Garment Patent Print |