| Patents for Duff Mfg. Co. |
Patents 1 -
13
of 13
      |
| Number | Date | Patentee | Title | Type |
| 1,052,921 | Feb. 11, 1913 | I.E. Hindman | Lifting-jack | |
| 1,054,413 | Feb. 25, 1913 | I.E. Hindman | Lifting-jack | vehicle mechanic |
| 1,089,703 | Mar. 10, 1914 | I.E. Hindman | Friction clutch for screw-jacks | screw jacks |
| 1,089,704 | Mar. 10, 1914 | I.E. Hindman | Rail-fastening | track and switches |
| 1,093,269 | Apr. 14, 1914 | I.E. Hindman | Jack | |
| 1,107,611 | Aug. 18, 1914 | I.E. Hindman | Lever-socket for lifting-jacks | vehicle mechanic |
| 1,147,476 | Jul. 20, 1915 | W.M. Alston, I.E. Hindman | Lifting-jack | |
| 1,151,232 | Aug. 24, 1915 | W.M. Alston, I.E. Hindman | Lifting-jack | |
| 1,165,380 | Dec. 28, 1915 | W.M. Alston, I.E. Hindman | Lifting-jack | |
| 1,228,210 | May 29, 1917 | I.E. Hindman | Screw-jack | screw jacks |
| 1,234,334 | Jul. 24, 1917 | I.E. Hindman | Brake mechanism for lifting-jacks | vehicle mechanic |
| 1,316,575 | Sep. 23, 1919 | I.E. Hindman | Lifting-jack | vehicle mechanic |
| 1,323,633 | Dec. 02, 1919 | I.E. Hindman | Lathe | metal lathes |
