| Patents for Duff Mfg. Co., Ltd. |
Patents 1 -
13
of 13
      |
| Number | Date | Patentee | Title | Type |
| 292,630 | Jan. 29, 1884 | S.K. Duff, J.B. Duff | Pipe-lifter for oil-wells | |
| 293,400 | Feb. 12, 1884 | J. Barrett | Lifting-jack | lifting jacks |
| 312,316 | Feb. 17, 1885 | J. Barrett | Lifting-jack | lifting jacks |
| RE10,574 | Mar. 24, 1885 | J. Barrett | Lifting-jack | lifting jacks |
| RE10,651 | Oct. 13, 1885 | J. Barrett | Lifting-jack | lifting jacks |
| 399,470 | Mar. 12, 1889 | J. Barrett | Lifting-jack | lifting jacks |
| RE11,051 | Dec. 31, 1889 | J. Barrett | Lifting-jack | lifting jacks |
| 455,993 | Jul. 14, 1891 | J. Barrett | Lifting-jack | lifting jacks |
| 455,994 | Jul. 14, 1891 | J. Barrett | Lifting-jack | lifting jacks |
| 455,995 | Jul. 14, 1891 | J. Barrett | Lifting-jack | lifting jacks |
| 511,923 | Jan. 02, 1894 | J. Barrett | Jack | lifting jacks |
| 511,924 | Jan. 02, 1894 | J. Barrett | Artesian-well apparatus | oil well pumps |
| 527,102 | Oct. 09, 1894 | J. Barrett | Jack | |
